diff options
Diffstat (limited to 'src/nix')
78 files changed, 3240 insertions, 431 deletions
diff --git a/src/nix/build.cc b/src/nix/build.cc index 67be4024b..c2974d983 100644 --- a/src/nix/build.cc +++ b/src/nix/build.cc @@ -43,22 +43,11 @@ struct CmdBuild : InstallablesCommand, MixDryRun, MixJSON, MixProfile return "build a derivation or fetch a store path"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To build and run GNU Hello from NixOS 17.03:", - "nix build -f channel:nixos-17.03 hello; ./result/bin/hello" - }, - Example{ - "To build the build.x86_64-linux attribute from release.nix:", - "nix build -f release.nix build.x86_64-linux" - }, - Example{ - "To make a profile point at GNU Hello:", - "nix build --profile /tmp/profile nixpkgs#hello" - }, - }; + return + #include "build.md" + ; } void run(ref<Store> store) override diff --git a/src/nix/build.md b/src/nix/build.md new file mode 100644 index 000000000..c2f3e387a --- /dev/null +++ b/src/nix/build.md @@ -0,0 +1,92 @@ +R""( + +# Examples + +* Build the default package from the flake in the current directory: + + ```console + # nix build + ``` + +* Build and run GNU Hello from the `nixpkgs` flake: + + ```console + # nix build nixpkgs#hello + # ./result/bin/hello + Hello, world! + ``` + +* Build GNU Hello and Cowsay, leaving two result symlinks: + + ```console + # nix build nixpkgs#hello nixpkgs#cowsay + # ls -l result* + lrwxrwxrwx 1 … result -> /nix/store/v5sv61sszx301i0x6xysaqzla09nksnd-hello-2.10 + lrwxrwxrwx 1 … result-1 -> /nix/store/rkfrm0z6x6jmi7d3gsmma4j53h15mg33-cowsay-3.03+dfsg2 + ``` + +* Build a specific output: + + ```console + # nix build nixpkgs#glibc.dev + # ls -ld ./result-dev + lrwxrwxrwx 1 … ./result-dev -> /nix/store/dkm3gwl0xrx0wrw6zi5x3px3lpgjhlw4-glibc-2.32-dev + ``` + +* Build attribute `build.x86_64-linux` from (non-flake) Nix expression + `release.nix`: + + ```console + # nix build -f release.nix build.x86_64-linux + ``` + +* Build a NixOS system configuration from a flake, and make a profile + point to the result: + + ```console + # nix build --profile /nix/var/nix/profiles/system \ + ~/my-configurations#nixosConfigurations.machine.config.system.build.toplevel + ``` + + (This is essentially what `nixos-rebuild` does.) + +* Build an expression specified on the command line: + + ```console + # nix build --impure --expr \ + 'with import <nixpkgs> {}; + runCommand "foo" { + buildInputs = [ hello ]; + } + "hello > $out"' + # cat ./result + Hello, world! + ``` + + Note that `--impure` is needed because we're using `<nixpkgs>`, + which relies on the `$NIX_PATH` environment variable. + +* Fetch a store path from the configured substituters, if it doesn't + already exist: + + ```console + # nix build /nix/store/rkfrm0z6x6jmi7d3gsmma4j53h15mg33-cowsay-3.03+dfsg2 + ``` + +# Description + +`nix build` builds the specified *installables*. Installables that +resolve to derivations are built (or substituted if possible). Store +path installables are substituted. + +Unless `--no-link` is specified, after a successful build, it creates +symlinks to the store paths of the installables. These symlinks have +the prefix `./result` by default; this can be overriden using the +`--out-link` option. Each symlink has a suffix `-<N>-<outname>`, where +*N* is the index of the installable (with the left-most installable +having index 0), and *outname* is the symbolic derivation output name +(e.g. `bin`, `dev` or `lib`). `-<N>` is omitted if *N* = 0, and +`-<outname>` is omitted if *outname* = `out` (denoting the default +output). + +)"" diff --git a/src/nix/bundle.cc b/src/nix/bundle.cc index eddd82f40..5f558b01e 100644 --- a/src/nix/bundle.cc +++ b/src/nix/bundle.cc @@ -40,14 +40,11 @@ struct CmdBundle : InstallableCommand return "bundle an application so that it works outside of the Nix store"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To bundle Hello:", - "nix bundle hello" - }, - }; + return + #include "bundle.md" + ; } Category category() override { return catSecondary; } diff --git a/src/nix/bundle.md b/src/nix/bundle.md new file mode 100644 index 000000000..5e2298376 --- /dev/null +++ b/src/nix/bundle.md @@ -0,0 +1,36 @@ +R""( + +# Examples + +* Bundle Hello: + + ```console + # nix bundle nixpkgs#hello + # ./hello + Hello, world! + ``` + +* Bundle a specific version of Nix: + + ```console + # nix bundle github:NixOS/nix/e3ddffb27e5fc37a209cfd843c6f7f6a9460a8ec + # ./nix --version + nix (Nix) 2.4pre20201215_e3ddffb + ``` + +# Description + +`nix bundle` packs the closure of the [Nix app](./nix3-run.md) +*installable* into a single self-extracting executable. See the +[`nix-bundle` homepage](https://github.com/matthewbauer/nix-bundle) +for more details. + +> **Note** +> +> This command only works on Linux. + +# Bundler definitions + +TODO + +)"" diff --git a/src/nix/cat.cc b/src/nix/cat.cc index 2ecffc9a5..e28ee3c50 100644 --- a/src/nix/cat.cc +++ b/src/nix/cat.cc @@ -37,6 +37,13 @@ struct CmdCatStore : StoreCommand, MixCat return "print the contents of a file in the Nix store on stdout"; } + std::string doc() override + { + return + #include "store-cat.md" + ; + } + void run(ref<Store> store) override { cat(store->getFSAccessor()); @@ -62,6 +69,13 @@ struct CmdCatNar : StoreCommand, MixCat return "print the contents of a file inside a NAR file on stdout"; } + std::string doc() override + { + return + #include "nar-cat.md" + ; + } + void run(ref<Store> store) override { cat(makeNarAccessor(make_ref<std::string>(readFile(narPath)))); diff --git a/src/nix/copy.cc b/src/nix/copy.cc index cb31aac8f..2394eb46d 100644 --- a/src/nix/copy.cc +++ b/src/nix/copy.cc @@ -54,32 +54,11 @@ struct CmdCopy : StorePathsCommand return "copy paths between Nix stores"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To copy Firefox from the local store to a binary cache in file:///tmp/cache:", - "nix copy --to file:///tmp/cache $(type -p firefox)" - }, - Example{ - "To copy the entire current NixOS system closure to another machine via SSH:", - "nix copy --to ssh://server /run/current-system" - }, - Example{ - "To copy a closure from another machine via SSH:", - "nix copy --from ssh://server /nix/store/a6cnl93nk1wxnq84brbbwr6hxw9gp2w9-blender-2.79-rc2" - }, -#ifdef ENABLE_S3 - Example{ - "To copy Hello to an S3 binary cache:", - "nix copy --to s3://my-bucket?region=eu-west-1 nixpkgs#hello" - }, - Example{ - "To copy Hello to an S3-compatible binary cache:", - "nix copy --to s3://my-bucket?region=eu-west-1&endpoint=example.com nixpkgs#hello" - }, -#endif - }; + return + #include "copy.md" + ; } Category category() override { return catSecondary; } diff --git a/src/nix/copy.md b/src/nix/copy.md new file mode 100644 index 000000000..25e0ddadc --- /dev/null +++ b/src/nix/copy.md @@ -0,0 +1,58 @@ +R""( + +# Examples + +* Copy Firefox from the local store to a binary cache in `/tmp/cache`: + + ```console + # nix copy --to file:///tmp/cache $(type -p firefox) + ``` + + Note the `file://` - without this, the destination is a chroot + store, not a binary cache. + +* Copy the entire current NixOS system closure to another machine via + SSH: + + ```console + # nix copy -s --to ssh://server /run/current-system + ``` + + The `-s` flag causes the remote machine to try to substitute missing + store paths, which may be faster if the link between the local and + remote machines is slower than the link between the remote machine + and its substituters (e.g. `https://cache.nixos.org`). + +* Copy a closure from another machine via SSH: + + ```console + # nix copy --from ssh://server /nix/store/a6cnl93nk1wxnq84brbbwr6hxw9gp2w9-blender-2.79-rc2 + ``` + +* Copy Hello to a binary cache in an Amazon S3 bucket: + + ```console + # nix copy --to s3://my-bucket?region=eu-west-1 nixpkgs#hello + ``` + + or to an S3-compatible storage system: + + ```console + # nix copy --to s3://my-bucket?region=eu-west-1&endpoint=example.com nixpkgs#hello + ``` + + Note that this only works if Nix is built with AWS support. + +* Copy a closure from `/nix/store` to the chroot store `/tmp/nix/nix/store`: + + ```console + # nix copy --to /tmp/nix nixpkgs#hello --no-check-sigs + ``` + +# Description + +`nix copy` copies store path closures between two Nix stores. The +source store is specified using `--from` and the destination using +`--to`. If one of these is omitted, it defaults to the local store. + +)"" diff --git a/src/nix/develop.cc b/src/nix/develop.cc index 457d94382..edd87f246 100644 --- a/src/nix/develop.cc +++ b/src/nix/develop.cc @@ -385,30 +385,11 @@ struct CmdDevelop : Common, MixEnvironment return "run a bash shell that provides the build environment of a derivation"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To get the build environment of GNU hello:", - "nix develop nixpkgs#hello" - }, - Example{ - "To get the build environment of the default package of flake in the current directory:", - "nix develop" - }, - Example{ - "To store the build environment in a profile:", - "nix develop --profile /tmp/my-shell nixpkgs#hello" - }, - Example{ - "To use a build environment previously recorded in a profile:", - "nix develop /tmp/my-shell" - }, - Example{ - "To replace all occurences of a store path with a writable directory:", - "nix develop --redirect nixpkgs#glibc.dev ~/my-glibc/outputs/dev" - }, - }; + return + #include "develop.md" + ; } void run(ref<Store> store) override @@ -495,14 +476,11 @@ struct CmdPrintDevEnv : Common return "print shell code that can be sourced by bash to reproduce the build environment of a derivation"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To apply the build environment of GNU hello to the current shell:", - ". <(nix print-dev-env nixpkgs#hello)" - }, - }; + return + #include "print-dev-env.md" + ; } Category category() override { return catUtility; } diff --git a/src/nix/develop.md b/src/nix/develop.md new file mode 100644 index 000000000..e71d9f8aa --- /dev/null +++ b/src/nix/develop.md @@ -0,0 +1,94 @@ +R""( + +# Examples + +* Start a shell with the build environment of the default package of + the flake in the current directory: + + ```console + # nix develop + ``` + + Typical commands to run inside this shell are: + + ```console + # configurePhase + # buildPhase + # installPhase + ``` + + Alternatively, you can run whatever build tools your project uses + directly, e.g. for a typical Unix project: + + ```console + # ./configure --prefix=$out + # make + # make install + ``` + +* Run a particular build phase directly: + + ```console + # nix develop --configure + # nix develop --build + # nix develop --check + # nix develop --install + # nix develop --installcheck + ``` + +* Start a shell with the build environment of GNU Hello: + + ```console + # nix develop nixpkgs#hello + ``` + +* Record a build environment in a profile: + + ```console + # nix develop --profile /tmp/my-build-env nixpkgs#hello + ``` + +* Use a build environment previously recorded in a profile: + + ```console + # nix develop /tmp/my-build-env + ``` + +* Replace all occurences of the store path corresponding to + `glibc.dev` with a writable directory: + + ```console + # nix develop --redirect nixpkgs#glibc.dev ~/my-glibc/outputs/dev + ``` + + Note that this is useful if you're running a `nix develop` shell for + `nixpkgs#glibc` in `~/my-glibc` and want to compile another package + against it. + +# Description + +`nix develop` starts a `bash` shell that provides an interactive build +environment nearly identical to what Nix would use to build +*installable*. Inside this shell, environment variables and shell +functions are set up so that you can interactively and incrementally +build your package. + +Nix determines the build environment by building a modified version of +the derivation *installable* that just records the environment +initialised by `stdenv` and exits. This build environment can be +recorded into a profile using `--profile`. + +The prompt used by the `bash` shell can be customised by setting the +`bash-prompt` and `bash-prompt-suffix` settings in `nix.conf` or in +the flake's `nixConfig` attribute. + +# Flake output attributes + +If no flake output attribute is given, `nix run` tries the following +flake output attributes: + +* `devShell.<system>` + +* `defaultPackage.<system>` + +)"" diff --git a/src/nix/diff-closures.cc b/src/nix/diff-closures.cc index f72b5eff7..0c7d531c1 100644 --- a/src/nix/diff-closures.cc +++ b/src/nix/diff-closures.cc @@ -121,14 +121,11 @@ struct CmdDiffClosures : SourceExprCommand return "show what packages and versions were added and removed between two closures"; } - Examples examples() override + std::string doc() override { - return { - { - "To show what got added and removed between two versions of the NixOS system profile:", - "nix store diff-closures /nix/var/nix/profiles/system-655-link /nix/var/nix/profiles/system-658-link", - }, - }; + return + #include "diff-closures.md" + ; } void run(ref<Store> store) override diff --git a/src/nix/diff-closures.md b/src/nix/diff-closures.md new file mode 100644 index 000000000..0294c0d8d --- /dev/null +++ b/src/nix/diff-closures.md @@ -0,0 +1,51 @@ +R""( + +# Examples + +* Show what got added and removed between two versions of the NixOS + system profile: + + ```console + # nix store diff-closures /nix/var/nix/profiles/system-655-link /nix/var/nix/profiles/system-658-link + acpi-call: 2020-04-07-5.8.16 → 2020-04-07-5.8.18 + baloo-widgets: 20.08.1 → 20.08.2 + bluez-qt: +12.6 KiB + dolphin: 20.08.1 → 20.08.2, +13.9 KiB + kdeconnect: 20.08.2 → ∅, -6597.8 KiB + kdeconnect-kde: ∅ → 20.08.2, +6599.7 KiB + … + ``` + +# Description + +This command shows the differences between the two closures *before* +and *after* with respect to the addition, removal, or version change +of packages, as well as changes in store path sizes. + +For each package name in the two closures (where a package name is +defined as the name component of a store path excluding the version), +if there is a change in the set of versions of the package, or a +change in the size of the store paths of more than 8 KiB, it prints a +line like this: + +```console +dolphin: 20.08.1 → 20.08.2, +13.9 KiB +``` + +No size change is shown if it's below the threshold. If the package +does not exist in either the *before* or *after* closures, it is +represented using `∅` (empty set) on the appropriate side of the +arrow. If a package has an empty version string, the version is +rendered as `ε` (epsilon). + +There may be multiple versions of a package in each closure. In that +case, only the changed versions are shown. Thus, + +```console +libfoo: 1.2, 1.3 → 1.4 +``` + +leaves open the possibility that there are other versions (e.g. `1.1`) +that exist in both closures. + +)"" diff --git a/src/nix/dump-path.cc b/src/nix/dump-path.cc index 256db64a9..c4edc894b 100644 --- a/src/nix/dump-path.cc +++ b/src/nix/dump-path.cc @@ -11,14 +11,11 @@ struct CmdDumpPath : StorePathCommand return "serialise a store path to stdout in NAR format"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To get a NAR from the binary cache https://cache.nixos.org/:", - "nix store dump-path --store https://cache.nixos.org/ /nix/store/7crrmih8c52r8fbnqb933dxrsp44md93-glibc-2.25" - }, - }; + return + #include "store-dump-path.md" + ; } void run(ref<Store> store, const StorePath & storePath) override @@ -49,14 +46,11 @@ struct CmdDumpPath2 : Command return "serialise a path to stdout in NAR format"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To serialise directory 'foo' as a NAR:", - "nix nar dump-path ./foo" - }, - }; + return + #include "nar-dump-path.md" + ; } void run() override diff --git a/src/nix/edit.cc b/src/nix/edit.cc index 51c16f5a9..6472dd27a 100644 --- a/src/nix/edit.cc +++ b/src/nix/edit.cc @@ -15,14 +15,11 @@ struct CmdEdit : InstallableCommand return "open the Nix expression of a Nix package in $EDITOR"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To open the Nix expression of the GNU Hello package:", - "nix edit nixpkgs#hello" - }, - }; + return + #include "edit.md" + ; } Category category() override { return catSecondary; } diff --git a/src/nix/edit.md b/src/nix/edit.md new file mode 100644 index 000000000..80563d06b --- /dev/null +++ b/src/nix/edit.md @@ -0,0 +1,31 @@ +R""( + +# Examples + +* Open the Nix expression of the GNU Hello package: + + ```console + # nix edit nixpkgs#hello + ``` + +* Get the filename and line number used by `nix edit`: + + ```console + # nix eval --raw nixpkgs#hello.meta.position + /nix/store/fvafw0gvwayzdan642wrv84pzm5bgpmy-source/pkgs/applications/misc/hello/default.nix:15 + ``` + +# Description + +This command opens the Nix expression of a derivation in an +editor. The filename and line number of the derivation are taken from +its `meta.position` attribute. Nixpkgs' `stdenv.mkDerivation` sets +this attribute to the location of the definition of the +`meta.description`, `version` or `name` derivation attributes. + +The editor to invoke is specified by the `EDITOR` environment +variable. It defaults to `cat`. If the editor is `emacs`, `nano` or +`vim`, it is passed the line number of the derivation using the +argument `+<lineno>`. + +)"" diff --git a/src/nix/eval.cc b/src/nix/eval.cc index ea82e5300..321df7495 100644 --- a/src/nix/eval.cc +++ b/src/nix/eval.cc @@ -40,30 +40,11 @@ struct CmdEval : MixJSON, InstallableCommand return "evaluate a Nix expression"; } - Examples examples() override + std::string doc() override { - return { - { - "To evaluate a Nix expression given on the command line:", - "nix eval --expr '1 + 2'" - }, - { - "To evaluate a Nix expression from a file or URI:", - "nix eval -f ./my-nixpkgs hello.name" - }, - { - "To get the current version of Nixpkgs:", - "nix eval --raw nixpkgs#lib.version" - }, - { - "To print the store path of the Hello package:", - "nix eval --raw nixpkgs#hello" - }, - { - "To get a list of checks in the 'nix' flake:", - "nix eval nix#checks.x86_64-linux --apply builtins.attrNames" - }, - }; + return + #include "eval.md" + ; } Category category() override { return catSecondary; } diff --git a/src/nix/eval.md b/src/nix/eval.md new file mode 100644 index 000000000..61334cde1 --- /dev/null +++ b/src/nix/eval.md @@ -0,0 +1,74 @@ +R""( + +# Examples + +* Evaluate a Nix expression given on the command line: + + ```console + # nix eval --expr '1 + 2' + ``` + +* Evaluate a Nix expression to JSON: + + ```console + # nix eval --json --expr '{ x = 1; }' + {"x":1} + ``` + +* Evaluate a Nix expression from a file: + + ```console + # nix eval -f ./my-nixpkgs hello.name + ``` + +* Get the current version of the `nixpkgs` flake: + + ```console + # nix eval --raw nixpkgs#lib.version + ``` + +* Print the store path of the Hello package: + + ```console + # nix eval --raw nixpkgs#hello + ``` + +* Get a list of checks in the `nix` flake: + + ```console + # nix eval nix#checks.x86_64-linux --apply builtins.attrNames + ``` + +* Generate a directory with the specified contents: + + ```console + # nix eval --write-to ./out --expr '{ foo = "bar"; subdir.bla = "123"; }' + # cat ./out/foo + bar + # cat ./out/subdir/bla + 123 + +# Description + +This command evaluates the Nix expression *installable* and prints the +result on standard output. + +# Output format + +`nix eval` can produce output in several formats: + +* By default, the evaluation result is printed as a Nix expression. + +* With `--json`, the evaluation result is printed in JSON format. Note + that this fails if the result contains values that are not + representable as JSON, such as functions. + +* With `--raw`, the evaluation result must be a string, which is + printed verbatim, without any quoting. + +* With `--write-to` *path*, the evaluation result must be a string or + a nested attribute set whose leaf values are strings. These strings + are written to files named *path*/*attrpath*. *path* must not + already exist. + +)"" diff --git a/src/nix/flake-archive.md b/src/nix/flake-archive.md new file mode 100644 index 000000000..85bbeeb16 --- /dev/null +++ b/src/nix/flake-archive.md @@ -0,0 +1,29 @@ +R""( + +# Examples + +* Copy the `dwarffs` flake and its dependencies to a binary cache: + + ```console + # nix flake archive --to file:///tmp/my-cache dwarffs + ``` + +* Fetch the `dwarffs` flake and its dependencies to the local Nix + store: + + ```console + # nix flake archive dwarffs + ``` + +* Print the store paths of the flake sources of NixOps without + fetching them: + + ```console + # nix flake archive --json --dry-run nixops + ``` + +# Description + +FIXME + +)"" diff --git a/src/nix/flake-check.md b/src/nix/flake-check.md new file mode 100644 index 000000000..dc079ba0c --- /dev/null +++ b/src/nix/flake-check.md @@ -0,0 +1,68 @@ +R""( + +# Examples + +* Evaluate the flake in the current directory, and build its checks: + + ```console + # nix flake check + ``` + +* Verify that the `patchelf` flake evaluates, but don't build its + checks: + + ```console + # nix flake check --no-build github:NixOS/patchelf + ``` + +# Description + +This command verifies that the flake specified by flake reference +*flake-url* can be evaluated successfully (as detailed below), and +that the derivations specified by the flake's `checks` output can be +built successfully. + +# Evaluation checks + +This following flake output attributes must be derivations: + +* `checks.`*system*`.`*name* +* `defaultPackage.`*system*` +* `devShell.`*system*` +* `nixosConfigurations.`*name*`.config.system.build.toplevel +* `packages.`*system*`.`*name* + +The following flake output attributes must be [app +definitions](./nix3-run.md): + +* `apps.`*system*`.`*name* +* `defaultApp.`*system*` + +The following flake output attributes must be [template +definitions](./nix3-flake-init.md): + +* `defaultTemplate` +* `templates`.`*name* + +The following flake output attributes must be *Nixpkgs overlays*: + +* `overlay` +* `overlays`.`*name* + +The following flake output attributes must be *NixOS modules*: + +* `nixosModule` +* `nixosModules`.`*name* + +The following flake output attributes must be +[bundlers](./nix3-bundle.md): + +* `bundlers`.`*name* +* `defaultBundler` + +In addition, the `hydraJobs` output is evaluated in the same way as +Hydra's `hydra-eval-jobs` (i.e. as a arbitrarily deeply nested +attribute set of derivations). Similarly, the +`legacyPackages`.*system* output is evaluated like `nix-env -qa`. + +)"" diff --git a/src/nix/flake-clone.md b/src/nix/flake-clone.md new file mode 100644 index 000000000..36cb96051 --- /dev/null +++ b/src/nix/flake-clone.md @@ -0,0 +1,18 @@ +R""( + +# Examples + +* Check out the source code of the `dwarffs` flake and build it: + + ```console + # nix flake clone dwarffs --dest dwarffs + # cd dwarffs + # nix build + ``` + +# Description + +This command performs a Git or Mercurial clone of the repository +containing the source code of the flake *flake-url*. + +)"" diff --git a/src/nix/flake-info.md b/src/nix/flake-info.md new file mode 100644 index 000000000..fda3171db --- /dev/null +++ b/src/nix/flake-info.md @@ -0,0 +1,99 @@ +R""( + +# Examples + +* Show what `nixpkgs` resolves to: + + ```console + # nix flake info nixpkgs + Resolved URL: github:NixOS/nixpkgs + Locked URL: github:NixOS/nixpkgs/b67ba0bfcc714453cdeb8d713e35751eb8b4c8f4 + Description: A collection of packages for the Nix package manager + Path: /nix/store/23qapccs6cfmwwrlq8kr41vz5vdmns3r-source + Revision: b67ba0bfcc714453cdeb8d713e35751eb8b4c8f4 + Last modified: 2020-12-23 12:36:12 + ``` + +* Show information about `dwarffs` in JSON format: + + ```console + # nix flake info dwarffs --json | jq . + { + "description": "A filesystem that fetches DWARF debug info from the Internet on demand", + "lastModified": 1597153508, + "locked": { + "lastModified": 1597153508, + "narHash": "sha256-VHg3MYVgQ12LeRSU2PSoDeKlSPD8PYYEFxxwkVVDRd0=", + "owner": "edolstra", + "repo": "dwarffs", + "rev": "d181d714fd36eb06f4992a1997cd5601e26db8f5", + "type": "github" + }, + "original": { + "id": "dwarffs", + "type": "indirect" + }, + "originalUrl": "flake:dwarffs", + "path": "/nix/store/hang3792qwdmm2n0d9nsrs5n6bsws6kv-source", + "resolved": { + "owner": "edolstra", + "repo": "dwarffs", + "type": "github" + }, + "resolvedUrl": "github:edolstra/dwarffs", + "revision": "d181d714fd36eb06f4992a1997cd5601e26db8f5", + "url": "github:edolstra/dwarffs/d181d714fd36eb06f4992a1997cd5601e26db8f5" + } + ``` + +# Description + +This command shows information about the flake specified by the flake +reference *flake-url*. It resolves the flake reference using the +[flake registry](./nix3-registry.md), fetches it, and prints some meta +data. This includes: + +* `Resolved URL`: If *flake-url* is a flake identifier, then this is + the flake reference that specifies its actual location, looked up in + the flake registry. + +* `Locked URL`: A flake reference that contains a commit or content + hash and thus uniquely identifies a specific flake version. + +* `Description`: A one-line description of the flake, taken from the + `description` field in `flake.nix`. + +* `Path`: The store path containing the source code of the flake. + +* `Revision`: The Git or Mercurial commit hash of the locked flake. + +* `Revisions`: The number of ancestors of the Git or Mercurial commit + of the locked flake. Note that this is not available for `github` + flakes. + +* `Last modified`: For Git or Mercurial flakes, this is the commit + time of the commit of the locked flake; for tarball flakes, it's the + most recent timestamp of any file inside the tarball. + +With `--json`, the output is a JSON object with the following fields: + +* `original` and `originalUrl`: The flake reference specified by the + user (*flake-url*) in attribute set and URL representation. + +* `resolved` and `resolvedUrl`: The resolved flake reference (see + above) in attribute set and URL representation. + +* `locked` and `lockedUrl`: The locked flake reference (see above) in + attribute set and URL representation. + +* `description`: See `Description` above. + +* `path`: See `Path` above. + +* `revision`: See `Revision` above. + +* `revCount`: See `Revisions` above. + +* `lastModified`: See `Last modified` above. + +)"" diff --git a/src/nix/flake-init.md b/src/nix/flake-init.md new file mode 100644 index 000000000..c66154ad5 --- /dev/null +++ b/src/nix/flake-init.md @@ -0,0 +1,54 @@ +R""( + +# Examples + +* Create a flake using the default template: + + ```console + # nix flake init + ``` + +* List available templates: + + ```console + # nix flake show templates + ``` + +* Create a flake from a specific template: + + ```console + # nix flake init -t templates#simpleContainer + ``` + +# Description + +This command creates a flake in the current directory by copying the +files of a template. It will not overwrite existing files. The default +template is `templates#defaultTemplate`, but this can be overriden +using `-t`. + +# Template definitions + +A flake can declare templates through its `templates` and +`defaultTemplate` output attributes. A template has two attributes: + +* `description`: A one-line description of the template, in CommonMark + syntax. + +* `path`: The path of the directory to be copied. + +Here is an example: + +``` +outputs = { self }: { + + templates.rust = { + path = ./rust; + description = "A simple Rust/Cargo project"; + }; + + templates.defaultTemplate = self.templates.rust; +} +``` + +)"" diff --git a/src/nix/flake-list-inputs.md b/src/nix/flake-list-inputs.md new file mode 100644 index 000000000..250e13be0 --- /dev/null +++ b/src/nix/flake-list-inputs.md @@ -0,0 +1,23 @@ +R""( + +# Examples + +* Show the inputs of the `hydra` flake: + + ```console + # nix flake list-inputs github:NixOS/hydra + github:NixOS/hydra/bde8d81876dfc02143e5070e42c78d8f0d83d6f7 + ├───nix: github:NixOS/nix/79aa7d95183cbe6c0d786965f0dbff414fd1aa67 + │ ├───lowdown-src: github:kristapsdz/lowdown/1705b4a26fbf065d9574dce47a94e8c7c79e052f + │ └───nixpkgs: github:NixOS/nixpkgs/ad0d20345219790533ebe06571f82ed6b034db31 + └───nixpkgs follows input 'nix/nixpkgs' + ``` + +# Description + +This command shows the inputs of the flake specified by the flake +referenced *flake-url*. Since it prints the locked inputs that result +from generating or updating the lock file, this command essentially +displays the contents of the flake's lock file in human-readable form. + +)"" diff --git a/src/nix/flake-new.md b/src/nix/flake-new.md new file mode 100644 index 000000000..725695c01 --- /dev/null +++ b/src/nix/flake-new.md @@ -0,0 +1,34 @@ +R""( + +# Examples + +* Create a flake using the default template in the directory `hello`: + + ```console + # nix flake new hello + ``` + +* List available templates: + + ```console + # nix flake show templates + ``` + +* Create a flake from a specific template in the directory `hello`: + + ```console + # nix flake new hello -t templates#trivial + ``` + +# Description + +This command creates a flake in the directory `dest-dir`, which must +not already exist. It's equivalent to: + +```console +# mkdir dest-dir +# cd dest-dir +# nix flake init +``` + +)"" diff --git a/src/nix/flake-show.md b/src/nix/flake-show.md new file mode 100644 index 000000000..1a42c44a0 --- /dev/null +++ b/src/nix/flake-show.md @@ -0,0 +1,38 @@ +R""( + +# Examples + +* Show the output attributes provided by the `patchelf` flake: + + ```console + github:NixOS/patchelf/f34751b88bd07d7f44f5cd3200fb4122bf916c7e + ├───checks + │ ├───aarch64-linux + │ │ └───build: derivation 'patchelf-0.12.20201207.f34751b' + │ ├───i686-linux + │ │ └───build: derivation 'patchelf-0.12.20201207.f34751b' + │ └───x86_64-linux + │ └───build: derivation 'patchelf-0.12.20201207.f34751b' + ├───defaultPackage + │ ├───aarch64-linux: package 'patchelf-0.12.20201207.f34751b' + │ ├───i686-linux: package 'patchelf-0.12.20201207.f34751b' + │ └───x86_64-linux: package 'patchelf-0.12.20201207.f34751b' + ├───hydraJobs + │ ├───build + │ │ ├───aarch64-linux: derivation 'patchelf-0.12.20201207.f34751b' + │ │ ├───i686-linux: derivation 'patchelf-0.12.20201207.f34751b' + │ │ └───x86_64-linux: derivation 'patchelf-0.12.20201207.f34751b' + │ ├───coverage: derivation 'patchelf-coverage-0.12.20201207.f34751b' + │ ├───release: derivation 'patchelf-0.12.20201207.f34751b' + │ └───tarball: derivation 'patchelf-tarball-0.12.20201207.f34751b' + └───overlay: Nixpkgs overlay + ``` + +# Description + +This command shows the output attributes provided by the flake +specified by flake reference *flake-url*. These are the top-level +attributes in the `outputs` of the flake, as well as lower-level +attributes for some standard outputs (e.g. `packages` or `checks`). + +)"" diff --git a/src/nix/flake-update.md b/src/nix/flake-update.md new file mode 100644 index 000000000..a2ffedd2a --- /dev/null +++ b/src/nix/flake-update.md @@ -0,0 +1,53 @@ +R""( + +# Examples + +* Update the `nixpkgs` and `nix` inputs of the flake in the current + directory: + + ```console + # nix flake update --update-input nixpkgs --update-input nix + * Updated 'nix': 'github:NixOS/nix/9fab14adbc3810d5cc1f88672fde1eee4358405c' -> 'github:NixOS/nix/8927cba62f5afb33b01016d5c4f7f8b7d0adde3c' + * Updated 'nixpkgs': 'github:NixOS/nixpkgs/3d2d8f281a27d466fa54b469b5993f7dde198375' -> 'github:NixOS/nixpkgs/a3a3dda3bacf61e8a39258a0ed9c924eeca8e293' + ``` + +* Recreate the lock file (i.e. update all inputs) and commit the new + lock file: + + ```console + # nix flake update --recreate-lock-file --commit-lock-file + … + warning: committed new revision '158bcbd9d6cc08ab859c0810186c1beebc982aad' + ``` + +# Description + +This command updates the lock file of a flake (`flake.lock`) so that +it contains a lock for every flake input specified in +`flake.nix`. Note that every command that operates on a flake will +also update the lock file if needed, and supports the same +flags. Therefore, + +```console +# nix flake update --update-input nixpkgs +# nix build +``` + +is equivalent to: + +```console +# nix build --update-input nixpkgs +``` + +Thus, this command is only useful if you want to update the lock file +separately from any other action such as building. + +> **Note** +> +> This command does *not* update locks that are already present unless +> you explicitly ask for it using `--update-input` or +> `--recreate-lock-file`. Thus, if the lock file already has locks for +> every input, then `nix flake update` (without arguments) does +> nothing. + +)"" diff --git a/src/nix/flake.cc b/src/nix/flake.cc index 066430c5d..2b91faa64 100644 --- a/src/nix/flake.cc +++ b/src/nix/flake.cc @@ -104,6 +104,13 @@ struct CmdFlakeUpdate : FlakeCommand return "update flake lock file"; } + std::string doc() override + { + return + #include "flake-update.md" + ; + } + void run(nix::ref<nix::Store> store) override { /* Use --refresh by default for 'nix flake update'. */ @@ -134,6 +141,13 @@ struct CmdFlakeInfo : FlakeCommand, MixJSON return "list info about a given flake"; } + std::string doc() override + { + return + #include "flake-info.md" + ; + } + void run(nix::ref<nix::Store> store) override { auto flake = getFlake(); @@ -153,6 +167,13 @@ struct CmdFlakeListInputs : FlakeCommand, MixJSON return "list flake inputs"; } + std::string doc() override + { + return + #include "flake-list-inputs.md" + ; + } + void run(nix::ref<nix::Store> store) override { auto flake = lockFlake(); @@ -211,6 +232,13 @@ struct CmdFlakeCheck : FlakeCommand return "check whether the flake evaluates and run its tests"; } + std::string doc() override + { + return + #include "flake-check.md" + ; + } + void run(nix::ref<nix::Store> store) override { settings.readOnlyMode = !build; @@ -631,22 +659,11 @@ struct CmdFlakeInit : CmdFlakeInitCommon return "create a flake in the current directory from a template"; } - Examples examples() override - { - return { - Example{ - "To create a flake using the default template:", - "nix flake init" - }, - Example{ - "To see available templates:", - "nix flake show templates" - }, - Example{ - "To create a flake from a specific template:", - "nix flake init -t templates#nixos-container" - }, - }; + std::string doc() override + { + return + #include "flake-init.md" + ; } CmdFlakeInit() @@ -662,6 +679,13 @@ struct CmdFlakeNew : CmdFlakeInitCommon return "create a flake in the specified directory from a template"; } + std::string doc() override + { + return + #include "flake-new.md" + ; + } + CmdFlakeNew() { expectArgs({ @@ -681,6 +705,13 @@ struct CmdFlakeClone : FlakeCommand return "clone flake repository"; } + std::string doc() override + { + return + #include "flake-clone.md" + ; + } + CmdFlakeClone() { addFlag({ @@ -720,22 +751,11 @@ struct CmdFlakeArchive : FlakeCommand, MixJSON, MixDryRun return "copy a flake and all its inputs to a store"; } - Examples examples() override - { - return { - Example{ - "To copy the dwarffs flake and its dependencies to a binary cache:", - "nix flake archive --to file:///tmp/my-cache dwarffs" - }, - Example{ - "To fetch the dwarffs flake and its dependencies to the local Nix store:", - "nix flake archive dwarffs" - }, - Example{ - "To print the store paths of the flake sources of NixOps without fetching them:", - "nix flake archive --json --dry-run nixops" - }, - }; + std::string doc() override + { + return + #include "flake-archive.md" + ; } void run(nix::ref<nix::Store> store) override @@ -797,6 +817,13 @@ struct CmdFlakeShow : FlakeCommand return "show the outputs provided by a flake"; } + std::string doc() override + { + return + #include "flake-show.md" + ; + } + void run(nix::ref<nix::Store> store) override { auto state = getEvalState(); @@ -955,6 +982,13 @@ struct CmdFlake : NixMultiCommand return "manage Nix flakes"; } + std::string doc() override + { + return + #include "flake.md" + ; + } + void run() override { if (!command) diff --git a/src/nix/flake.md b/src/nix/flake.md new file mode 100644 index 000000000..440c45dd1 --- /dev/null +++ b/src/nix/flake.md @@ -0,0 +1,566 @@ +R""( + +# Description + +`nix flake` provides subcommands for creating, modifying and querying +*Nix flakes*. Flakes are the unit for packaging Nix code in a +reproducible and discoverable way. They can have dependencies on other +flakes, making it possible to have multi-repository Nix projects. + +A flake is a filesystem tree (typically fetched from a Git repository +or a tarball) that contains a file named `flake.nix` in the root +directory. `flake.nix` specifies some metadata about the flake such as +dependencies (called *inputs*), as well as its *outputs* (the Nix +values such as packages or NixOS modules provided by the flake). + +# Flake references + +Flake references (*flakerefs*) are a way to specify the location of a +flake. These have two different forms: + +* An attribute set representation, e.g. + + ```nix + { + type = "github"; + owner = "NixOS"; + repo = "nixpkgs"; + } + ``` + + The only required attribute is `type`. The supported types are + listed below. + +* A URL-like syntax, e.g. + + ``` + github:NixOS/nixpkgs + ``` + + These are used on the command line as a more convenient alternative + to the attribute set representation. For instance, in the command + + ```console + # nix build github:NixOS/nixpkgs#hello + ``` + + `github:NixOS/nixpkgs` is a flake reference (while `hello` is an + output attribute). They are also allowed in the `inputs` attribute + of a flake, e.g. + + ```nix + inputs.nixpkgs.url = github:NixOS/nixpkgs; + ``` + + is equivalent to + + ```nix + inputs.nixpkgs = { + type = "github"; + owner = "NixOS"; + repo = "nixpkgs"; + }; + ``` + +## Examples + +Here are some examples of flake references in their URL-like representation: + +* `.`: The flake in the current directory. +* `/home/alice/src/patchelf`: A flake in some other directory. +* `nixpkgs`: The `nixpkgs` entry in the flake registry. +* `nixpkgs/a3a3dda3bacf61e8a39258a0ed9c924eeca8e293`: The `nixpkgs` + entry in the flake registry, with its Git revision overriden to a + specific value. +* `github:NixOS/nixpkgs`: The `master` branch of the `NixOS/nixpkgs` + repository on GitHub. +* `github:NixOS/nixpkgs/nixos-20.09`: The `nixos-20.09` branch of the + `nixpkgs` repository. +* `github:NixOS/nixpkgs/a3a3dda3bacf61e8a39258a0ed9c924eeca8e293`: A + specific revision of the `nixpkgs` repository. +* `github:edolstra/nix-warez?dir=blender`: A flake in a subdirectory + of a GitHub repository. +* `git+https://github.com/NixOS/patchelf`: A Git repository. +* `git+https://github.com/NixOS/patchelf?ref=master`: A specific + branch of a Git repository. +* `git+https://github.com/NixOS/patchelf?ref=master&rev=f34751b88bd07d7f44f5cd3200fb4122bf916c7e`: + A specific branch *and* revision of a Git repository. +* `https://github.com/NixOS/patchelf/archive/master.tar.gz`: A tarball + flake. + +## Flake reference attributes + +The following generic flake reference attributes are supported: + +* `dir`: The subdirectory of the flake in which `flake.nix` is + located. This parameter enables having multiple flakes in a + repository or tarball. The default is the root directory of the + flake. + +* `narHash`: The hash of the NAR serialisation (in SRI format) of the + contents of the flake. This is useful for flake types such as + tarballs that lack a unique content identifier such as a Git commit + hash. + +In addition, the following attributes are common to several flake +reference types: + +* `rev`: A Git or Mercurial commit hash. + +* `ref`: A Git or Mercurial branch or tag name. + +Finally, some attribute are typically not specified by the user, but +can occur in *locked* flake references and are available to Nix code: + +* `revCount`: The number of ancestors of the commit `rev`. + +* `lastModified`: The timestamp (in seconds since the Unix epoch) of + the last modification of this version of the flake. For + Git/Mercurial flakes, this is the commit time of commit *rev*, while + for tarball flakes, it's the most recent timestamp of any file + inside the tarball. + +## Types + +Currently the `type` attribute can be one of the following: + +* `path`: arbitrary local directories, or local Git trees. The + required attribute `path` specifies the path of the flake. The URL + form is + + ``` + [path:]<path>(\?<params)? + ``` + + where *path* is an absolute path. + + *path* must be a directory in the file system containing a file + named `flake.nix`. + + If the directory or any of its parents is a Git repository, then + this is essentially equivalent to `git+file://<path>` (see below), + except that the `dir` parameter is derived automatically. For + example, if `/foo/bar` is a Git repository, then the flake reference + `/foo/bar/flake` is equivalent to `/foo/bar?dir=flake`. + + If the directory is not inside a Git repository, then the flake + contents is the entire contents of *path*. + + *path* generally must be an absolute path. However, on the command + line, it can be a relative path (e.g. `.` or `./foo`) which is + interpreted as relative to the current directory. In this case, it + must start with `.` to avoid ambiguity with registry lookups + (e.g. `nixpkgs` is a registry lookup; `./nixpkgs` is a relative + path). + +* `git`: Git repositories. The location of the repository is specified + by the attribute `url`. + + They have the URL form + + ``` + git(+http|+https|+ssh|+git|+file|):(//<server>)?<path>(\?<params>)? + ``` + + The `ref` attribute defaults to `master`. + + The `rev` attribute must denote a commit that exists in the branch + or tag specified by the `ref` attribute, since Nix doesn't do a full + clone of the remote repository by default (and the Git protocol + doesn't allow fetching a `rev` without a known `ref`). The default + is the commit currently pointed to by `ref`. + + For example, the following are valid Git flake references: + + * `git+https://example.org/my/repo` + * `git+https://example.org/my/repo?dir=flake1` + * `git+ssh://git@github.com/NixOS/nix?ref=v1.2.3` + * `git://github.com/edolstra/dwarffs?ref=unstable&rev=e486d8d40e626a20e06d792db8cc5ac5aba9a5b4` + * `git+file:///home/my-user/some-repo/some-repo` + +* `mercurial`: Mercurial repositories. The URL form is similar to the + `git` type, except that the URL schema must be one of `hg+http`, + `hg+https`, `hg+ssh` or `hg+file`. + +* `tarball`: Tarballs. The location of the tarball is specified by the + attribute `url`. + + In URL form, the schema must be `http://`, `https://` or `file://` + URLs and the extension must be `.zip`, `.tar`, `.tar.gz`, `.tar.xz` + or `.tar.bz2`. + +* `github`: A more efficient way to fetch repositories from + GitHub. The following attributes are required: + + * `owner`: The owner of the repository. + + * `repo`: The name of the repository. + + These are downloaded as tarball archives, rather than + through Git. This is often much faster and uses less disk space + since it doesn't require fetching the entire history of the + repository. On the other hand, it doesn't allow incremental fetching + (but full downloads are often faster than incremental fetches!). + + The URL syntax for `github` flakes is: + + ``` + github:<owner>/<repo>(/<rev-or-ref>)?(\?<params>)? + ``` + + `<rev-or-ref>` specifies the name of a branch or tag (`ref`), or a + commit hash (`rev`). Note that unlike Git, GitHub allows fetching by + commit hash without specifying a branch or tag. + + Some examples: + + * `github:edolstra/dwarffs` + * `github:edolstra/dwarffs/unstable` + * `github:edolstra/dwarffs/d3f2baba8f425779026c6ec04021b2e927f61e31` + +* `indirect`: Indirections through the flake registry. These have the + form + + ``` + [flake:]<flake-id>(/<rev-or-ref>(/rev)?)? + ``` + + These perform a lookup of `<flake-id>` in the flake registry. or + example, `nixpkgs` and `nixpkgs/release-20.09` are indirect flake + references. The specified `rev` and/or `ref` are merged with the + entry in the registry; see [nix registry](./nix3-registry.md) for + details. + +# Flake format + +As an example, here is a simple `flake.nix` that depends on the +Nixpkgs flake and provides a single package (i.e. an installable +derivation): + +```nix +{ + description = "A flake for building Hello World"; + + inputs.nixpkgs.url = github:NixOS/nixpkgs/nixos-20.03; + + outputs = { self, nixpkgs }: { + + defaultPackage.x86_64-linux = + # Notice the reference to nixpkgs here. + with import nixpkgs { system = "x86_64-linux"; }; + stdenv.mkDerivation { + name = "hello"; + src = self; + buildPhase = "gcc -o hello ./hello.c"; + installPhase = "mkdir -p $out/bin; install -t $out/bin hello"; + }; + + }; +} +``` + +The following attributes are supported in `flake.nix`: + +* `description`: A short, one-line description of the flake. + +* `inputs`: An attrset specifying the dependencies of the flake + (described below). + +* `outputs`: A function that, given an attribute set containing the + outputs of each of the input flakes keyed by their identifier, + yields the Nix values provided by this flake. Thus, in the example + above, `inputs.nixpkgs` contains the result of the call to the + `outputs` function of the `nixpkgs` flake. + + In addition to the outputs of each input, each input in `inputs` + also contains some metadata about the inputs. These are: + + * `outPath`: The path in the Nix store of the flake's source tree. + + * `rev`: The commit hash of the flake's repository, if applicable. + + * `revCount`: The number of ancestors of the revision `rev`. This is + not available for `github` repositories, since they're fetched as + tarballs rather than as Git repositories. + + * `lastModifiedDate`: The commit time of the revision `rev`, in the + format `%Y%m%d%H%M%S` (e.g. `20181231100934`). Unlike `revCount`, + this is available for both Git and GitHub repositories, so it's + useful for generating (hopefully) monotonically increasing version + strings. + + * `lastModified`: The commit time of the revision `rev` as an integer + denoting the number of seconds since 1970. + + * `narHash`: The SHA-256 (in SRI format) of the NAR serialization of + the flake's source tree. + + The value returned by the `outputs` function must be an attribute + set. The attributes can have arbitrary values; however, various + `nix` subcommands require specific attributes to have a specific + value (e.g. `packages.x86_64-linux` must be an attribute set of + derivations built for the `x86_64-linux` platform). + +## Flake inputs + +The attribute `inputs` specifies the dependencies of a flake, as an +attrset mapping input names to flake references. For example, the +following specifies a dependency on the `nixpkgs` and `import-cargo` +repositories: + +```nix +# A GitHub repository. +inputs.import-cargo = { + type = "github"; + owner = "edolstra"; + repo = "import-cargo"; +}; + +# An indirection through the flake registry. +inputs.nixpkgs = { + type = "indirect"; + id = "nixpkgs"; +}; +``` + +Alternatively, you can use the URL-like syntax: + +```nix +inputs.import-cargo.url = github:edolstra/import-cargo; +inputs.nixpkgs.url = "nixpkgs"; +``` + +Each input is fetched, evaluated and passed to the `outputs` function +as a set of attributes with the same name as the corresponding +input. The special input named `self` refers to the outputs and source +tree of *this* flake. Thus, a typical `outputs` function looks like +this: + +```nix +outputs = { self, nixpkgs, import-cargo }: { + ... outputs ... +}; +``` + +It is also possible to omit an input entirely and *only* list it as +expected function argument to `outputs`. Thus, + +```nix +outputs = { self, nixpkgs }: ...; +``` + +without an `inputs.nixpkgs` attribute is equivalent to + +```nix +inputs.nixpkgs = { + type = "indirect"; + id = "nixpkgs"; +}; +``` + +Repositories that don't contain a `flake.nix` can also be used as +inputs, by setting the input's `flake` attribute to `false`: + +```nix +inputs.grcov = { + type = "github"; + owner = "mozilla"; + repo = "grcov"; + flake = false; +}; + +outputs = { self, nixpkgs, grcov }: { + packages.x86_64-linux.grcov = stdenv.mkDerivation { + src = grcov; + ... + }; +}; +``` + +Transitive inputs can be overriden from a `flake.nix` file. For +example, the following overrides the `nixpkgs` input of the `nixops` +input: + +```nix +inputs.nixops.inputs.nixpkgs = { + type = "github"; + owner = "my-org"; + repo = "nixpkgs"; +}; +``` + +It is also possible to "inherit" an input from another input. This is +useful to minimize flake dependencies. For example, the following sets +the `nixpkgs` input of the top-level flake to be equal to the +`nixpkgs` input of the `dwarffs` input of the top-level flake: + +```nix +inputs.nixops.follows = "dwarffs/nixpkgs"; +``` + +The value of the `follows` attribute is a `/`-separated sequence of +input names denoting the path of inputs to be followed from the root +flake. + +Overrides and `follows` can be combined, e.g. + +```nix +inputs.nixops.inputs.nixpkgs.follows = "dwarffs/nixpkgs"; +``` + +sets the `nixpkgs` input of `nixops` to be the same as the `nixpkgs` +input of `dwarffs`. It is worth noting, however, that it is generally +not useful to eliminate transitive `nixpkgs` flake inputs in this +way. Most flakes provide their functionality through Nixpkgs overlays +or NixOS modules, which are composed into the top-level flake's +`nixpkgs` input; so their own `nixpkgs` input is usually irrelevant. + +# Lock files + +Inputs specified in `flake.nix` are typically "unlocked" in the sense +that they don't specify an exact revision. To ensure reproducibility, +Nix will automatically generate and use a *lock file* called +`flake.lock` in the flake's directory. The lock file contains a graph +structure isomorphic to the graph of dependencies of the root +flake. Each node in the graph (except the root node) maps the +(usually) unlocked input specifications in `flake.nix` to locked input +specifications. Each node also contains some metadata, such as the +dependencies (outgoing edges) of the node. + +For example, if `flake.nix` has the inputs in the example above, then +the resulting lock file might be: + +```json +{ + "version": 7, + "root": "n1", + "nodes": { + "n1": { + "inputs": { + "nixpkgs": "n2", + "import-cargo": "n3", + "grcov": "n4" + } + }, + "n2": { + "inputs": {}, + "locked": { + "owner": "edolstra", + "repo": "nixpkgs", + "rev": "7f8d4b088e2df7fdb6b513bc2d6941f1d422a013", + "type": "github", + "lastModified": 1580555482, + "narHash": "sha256-OnpEWzNxF/AU4KlqBXM2s5PWvfI5/BS6xQrPvkF5tO8=" + }, + "original": { + "id": "nixpkgs", + "type": "indirect" + } + }, + "n3": { + "inputs": {}, + "locked": { + "owner": "edolstra", + "repo": "import-cargo", + "rev": "8abf7b3a8cbe1c8a885391f826357a74d382a422", + "type": "github", + "lastModified": 1567183309, + "narHash": "sha256-wIXWOpX9rRjK5NDsL6WzuuBJl2R0kUCnlpZUrASykSc=" + }, + "original": { + "owner": "edolstra", + "repo": "import-cargo", + "type": "github" + } + }, + "n4": { + "inputs": {}, + "locked": { + "owner": "mozilla", + "repo": "grcov", + "rev": "989a84bb29e95e392589c4e73c29189fd69a1d4e", + "type": "github", + "lastModified": 1580729070, + "narHash": "sha256-235uMxYlHxJ5y92EXZWAYEsEb6mm+b069GAd+BOIOxI=" + }, + "original": { + "owner": "mozilla", + "repo": "grcov", + "type": "github" + }, + "flake": false + } + } +} +``` + +This graph has 4 nodes: the root flake, and its 3 dependencies. The +nodes have arbitrary labels (e.g. `n1`). The label of the root node of +the graph is specified by the `root` attribute. Nodes contain the +following fields: + +* `inputs`: The dependencies of this node, as a mapping from input + names (e.g. `nixpkgs`) to node labels (e.g. `n2`). + +* `original`: The original input specification from `flake.lock`, as a + set of `builtins.fetchTree` arguments. + +* `locked`: The locked input specification, as a set of + `builtins.fetchTree` arguments. Thus, in the example above, when we + build this flake, the input `nixpkgs` is mapped to revision + `7f8d4b088e2df7fdb6b513bc2d6941f1d422a013` of the `edolstra/nixpkgs` + repository on GitHub. + + It also includes the attribute `narHash`, specifying the expected + contents of the tree in the Nix store (as computed by `nix + hash-path`), and may include input-type-specific attributes such as + the `lastModified` or `revCount`. The main reason for these + attributes is to allow flake inputs to be substituted from a binary + cache: `narHash` allows the store path to be computed, while the + other attributes are necessary because they provide information not + stored in the store path. + +* `flake`: A Boolean denoting whether this is a flake or non-flake + dependency. Corresponds to the `flake` attribute in the `inputs` + attribute in `flake.nix`. + +The `original` and `locked` attributes are omitted for the root +node. This is because we cannot record the commit hash or content hash +of the root flake, since modifying `flake.lock` will invalidate these. + +The graph representation of lock files allows circular dependencies +between flakes. For example, here are two flakes that reference each +other: + +```nix +{ + inputs.b = ... location of flake B ...; + # Tell the 'b' flake not to fetch 'a' again, to ensure its 'a' is + # *this* 'a'. + inputs.b.inputs.a.follows = ""; + outputs = { self, b }: { + foo = 123 + b.bar; + xyzzy = 1000; + }; +} +``` + +and + +```nix +{ + inputs.a = ... location of flake A ...; + inputs.a.inputs.b.follows = ""; + outputs = { self, a }: { + bar = 456 + a.xyzzy; + }; +} +``` + +Lock files transitively lock direct as well as indirect +dependencies. That is, if a lock file exists and is up to date, Nix +will not look at the lock files of dependencies. However, lock file +generation itself *does* use the lock files of dependencies by +default. + +)"" diff --git a/src/nix/help.md b/src/nix/help.md new file mode 100644 index 000000000..734f35028 --- /dev/null +++ b/src/nix/help.md @@ -0,0 +1,17 @@ +R""( + +# Examples + +* Show help about `nix` in general: + + ```console + # nix help + ``` + +* Show help about a particular subcommand: + + ```console + # nix help flake info + ``` + +)"" diff --git a/src/nix/log.cc b/src/nix/log.cc index 33a3053f5..67d3742d6 100644 --- a/src/nix/log.cc +++ b/src/nix/log.cc @@ -13,22 +13,11 @@ struct CmdLog : InstallableCommand return "show the build log of the specified packages or paths, if available"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To get the build log of GNU Hello:", - "nix log nixpkgs#hello" - }, - Example{ - "To get the build log of a specific path:", - "nix log /nix/store/lmngj4wcm9rkv3w4dfhzhcyij3195hiq-thunderbird-52.2.1" - }, - Example{ - "To get a build log from a specific binary cache:", - "nix log --store https://cache.nixos.org nixpkgs#hello" - }, - }; + return + #include "log.md" + ; } Category category() override { return catSecondary; } diff --git a/src/nix/log.md b/src/nix/log.md new file mode 100644 index 000000000..1c76226a3 --- /dev/null +++ b/src/nix/log.md @@ -0,0 +1,40 @@ +R""( + +# Examples + +* Get the build log of GNU Hello: + + ```console + # nix log nixpkgs#hello + ``` + +* Get the build log of a specific store path: + + ```console + # nix log /nix/store/lmngj4wcm9rkv3w4dfhzhcyij3195hiq-thunderbird-52.2.1 + ``` + +* Get a build log from a specific binary cache: + + ```console + # nix log --store https://cache.nixos.org nixpkgs#hello + ``` + +# Description + +This command prints the log of a previous build of the derivation +*installable* on standard output. + +Nix looks for build logs in two places: + +* In the directory `/nix/var/log/nix/drvs`, which contains logs for + locally built derivations. + +* In the binary caches listed in the `substituters` setting. Logs + should be named `<cache>/log/<base-name-of-store-path>`, where + `store-path` is a derivation, + e.g. `https://cache.nixos.org/log/dvmig8jgrdapvbyxb1rprckdmdqx08kv-hello-2.10.drv`. + For non-derivation store paths, Nix will first try to determine the + deriver by fetching the `.narinfo` file for this store path. + +)"" diff --git a/src/nix/ls.cc b/src/nix/ls.cc index 1f5ed6913..d48287f27 100644 --- a/src/nix/ls.cc +++ b/src/nix/ls.cc @@ -75,6 +75,8 @@ struct MixLs : virtual Args, MixJSON if (json) { JSONPlaceholder jsonRoot(std::cout); + if (showDirectory) + throw UsageError("'--directory' is useless with '--json'"); listNar(jsonRoot, accessor, path, recursive); } else listText(accessor); @@ -92,19 +94,16 @@ struct CmdLsStore : StoreCommand, MixLs }); } - Examples examples() override + std::string description() override { - return { - Example{ - "To list the contents of a store path in a binary cache:", - "nix store ls --store https://cache.nixos.org/ -lR /nix/store/0i2jd68mp5g6h2sa5k9c85rb80sn8hi9-hello-2.10" - }, - }; + return "show information about a path in the Nix store"; } - std::string description() override + std::string doc() override { - return "show information about a path in the Nix store"; + return + #include "store-ls.md" + ; } void run(ref<Store> store) override @@ -127,14 +126,11 @@ struct CmdLsNar : Command, MixLs expectArg("path", &path); } - Examples examples() override + std::string doc() override { - return { - Example{ - "To list a specific file in a NAR:", - "nix nar ls -l hello.nar /bin/hello" - }, - }; + return + #include "nar-ls.md" + ; } std::string description() override diff --git a/src/nix/main.cc b/src/nix/main.cc index e7a15dec9..b2406fafe 100644 --- a/src/nix/main.cc +++ b/src/nix/main.cc @@ -184,6 +184,13 @@ struct NixArgs : virtual MultiCommand, virtual MixCommonArgs { return "a tool for reproducible and declarative configuration management"; } + + std::string doc() override + { + return + #include "nix.md" + ; + } }; static void showHelp(std::vector<std::string> subcommand) @@ -205,21 +212,14 @@ struct CmdHelp : Command std::string description() override { - return "show help about 'nix' or a particular subcommand"; + return "show help about `nix` or a particular subcommand"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To show help about 'nix' in general:", - "nix help" - }, - Example{ - "To show help about a particular subcommand:", - "nix help run" - }, - }; + return + #include "help.md" + ; } void run() override diff --git a/src/nix/make-content-addressable.cc b/src/nix/make-content-addressable.cc index 5165c4804..f5bdc7e65 100644 --- a/src/nix/make-content-addressable.cc +++ b/src/nix/make-content-addressable.cc @@ -15,21 +15,14 @@ struct CmdMakeContentAddressable : StorePathsCommand, MixJSON std::string description() override { - return "rewrite a path or closure to content-addressable form"; + return "rewrite a path or closure to content-addressed form"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To create a content-addressable representation of GNU Hello (but not its dependencies):", - "nix store make-content-addressable nixpkgs#hello" - }, - Example{ - "To compute a content-addressable representation of the current NixOS system closure:", - "nix store make-content-addressable -r /run/current-system" - }, - }; + return + #include "make-content-addressable.md" + ; } void run(ref<Store> store, StorePaths storePaths) override diff --git a/src/nix/make-content-addressable.md b/src/nix/make-content-addressable.md new file mode 100644 index 000000000..3dd847edc --- /dev/null +++ b/src/nix/make-content-addressable.md @@ -0,0 +1,59 @@ +R""( + +# Examples + +* Create a content-addressed representation of the closure of GNU Hello: + + ```console + # nix store make-content-addressable -r nixpkgs#hello + … + rewrote '/nix/store/v5sv61sszx301i0x6xysaqzla09nksnd-hello-2.10' to '/nix/store/5skmmcb9svys5lj3kbsrjg7vf2irid63-hello-2.10' + ``` + + Since the resulting paths are content-addressed, they are always + trusted and don't need signatures to copied to another store: + + ```console + # nix copy --to /tmp/nix --trusted-public-keys '' /nix/store/5skmmcb9svys5lj3kbsrjg7vf2irid63-hello-2.10 + ``` + + By contrast, the original closure is input-addressed, so it does + need signatures to be trusted: + + ```console + # nix copy --to /tmp/nix --trusted-public-keys '' nixpkgs#hello + cannot add path '/nix/store/zy9wbxwcygrwnh8n2w9qbbcr6zk87m26-libunistring-0.9.10' because it lacks a valid signature + ``` + +* Create a content-addressed representation of the current NixOS + system closure: + + ```console + # nix store make-content-addressable -r /run/current-system + ``` + +# Description + +This command converts the closure of the store paths specified by +*installables* to content-addressed form. Nix store paths are usually +*input-addressed*, meaning that the hash part of the store path is +computed from the contents of the derivation (i.e., the build-time +dependency graph). Input-addressed paths need to be signed by a +trusted key if you want to import them into a store, because we need +to trust that the contents of the path were actually built by the +derivation. + +By contrast, in a *content-addressed* path, the hash part is computed +from the contents of the path. This allows the contents of the path to +be verified without any additional information such as +signatures. This means that a command like + +```console +# nix store build /nix/store/5skmmcb9svys5lj3kbsrjg7vf2irid63-hello-2.10 \ + --substituters https://my-cache.example.org +``` + +will succeed even if the binary cache `https://my-cache.example.org` +doesn't present any signatures. + +)"" diff --git a/src/nix/nar-cat.md b/src/nix/nar-cat.md new file mode 100644 index 000000000..55c481a28 --- /dev/null +++ b/src/nix/nar-cat.md @@ -0,0 +1,19 @@ +R""( + +# Examples + +* List a file in a NAR and pipe it through `gunzip`: + + ```console + # nix nar cat ./hello.nar /share/man/man1/hello.1.gz | gunzip + .\" DO NOT MODIFY THIS FILE! It was generated by help2man 1.46.4. + .TH HELLO "1" "November 2014" "hello 2.10" "User Commands" + … + ``` + +# Description + +This command prints on standard output the contents of the regular +file *path* inside the NAR file *nar*. + +)"" diff --git a/src/nix/nar-dump-path.md b/src/nix/nar-dump-path.md new file mode 100644 index 000000000..26191ad25 --- /dev/null +++ b/src/nix/nar-dump-path.md @@ -0,0 +1,17 @@ +R""( + +# Examples + +* To serialise directory `foo` as a NAR: + + ```console + # nix nar dump-path ./foo > foo.nar + ``` + +# Description + +This command generates a NAR file containing the serialisation of +*path*, which must contain only regular files, directories and +symbolic links. The NAR is written to standard output. + +)"" diff --git a/src/nix/nar-ls.md b/src/nix/nar-ls.md new file mode 100644 index 000000000..d373f9715 --- /dev/null +++ b/src/nix/nar-ls.md @@ -0,0 +1,24 @@ +R""( + +# Examples + +* To list a specific file in a NAR: + + ```console + # nix nar ls -l ./hello.nar /bin/hello + -r-xr-xr-x 38184 hello + ``` + +* To recursively list the contents of a directory inside a NAR, in JSON + format: + + ```console + # nix nar ls --json -R ./hello.nar /bin + {"type":"directory","entries":{"hello":{"type":"regular","size":38184,"executable":true,"narOffset":400}}} + ``` + +# Description + +This command shows information about a *path* inside NAR file *nar*. + +)"" diff --git a/src/nix/nar.cc b/src/nix/nar.cc index e239ce96a..0775d3c25 100644 --- a/src/nix/nar.cc +++ b/src/nix/nar.cc @@ -9,7 +9,14 @@ struct CmdNar : NixMultiCommand std::string description() override { - return "query the contents of NAR files"; + return "create or inspect NAR files"; + } + + std::string doc() override + { + return + #include "nar.md" + ; } Category category() override { return catUtility; } diff --git a/src/nix/nar.md b/src/nix/nar.md new file mode 100644 index 000000000..a83b5c764 --- /dev/null +++ b/src/nix/nar.md @@ -0,0 +1,13 @@ +R""( + +# Description + +`nix nar` provides several subcommands for creating and inspecting +*Nix Archives* (NARs). + +# File format + +For the definition of the NAR file format, see Figure 5.2 in +https://edolstra.github.io/pubs/phd-thesis.pdf. + +)"" diff --git a/src/nix/nix.md b/src/nix/nix.md new file mode 100644 index 000000000..d10de7c01 --- /dev/null +++ b/src/nix/nix.md @@ -0,0 +1,119 @@ +R""( + +# Examples + +* Create a new flake: + + ```console + # nix flake new hello + # cd hello + ``` + +* Build the flake in the current directory: + + ```console + # nix build + # ./result/bin/hello + Hello, world! + ``` + +* Run the flake in the current directory: + + ```console + # nix run + Hello, world! + ``` + +* Start a development shell for hacking on this flake: + + ```console + # nix develop + # unpackPhase + # cd hello-* + # configurePhase + # buildPhase + # ./hello + Hello, world! + # installPhase + # ../outputs/out/bin/hello + Hello, world! + ``` + +# Description + +Nix is a tool for building software, configurations and other +artifacts in a reproducible and declarative way. For more information, +see the [Nix homepage](https://nixos.org/) or the [Nix +manual](https://nixos.org/manual/nix/stable/). + +# Installables + +Many `nix` subcommands operate on one or more *installables*. These are +command line arguments that represent something that can be built in +the Nix store. Here are the recognised types of installables: + +* **Flake output attributes**: `nixpkgs#hello` + + These have the form *flakeref*[`#`*attrpath*], where *flakeref* is a + flake reference and *attrpath* is an optional attribute path. For + more information on flakes, see [the `nix flake` manual + page](./nix3-flake.md). Flake references are most commonly a flake + identifier in the flake registry (e.g. `nixpkgs`) or a path + (e.g. `/path/to/my-flake` or `.`). + + If *attrpath* is omitted, Nix tries some default values; for most + subcommands, the default is `defaultPackage.`*system* + (e.g. `defaultPackage.x86_64-linux`), but some subcommands have + other defaults. If *attrpath* *is* specified, *attrpath* is + interpreted as relative to one or more prefixes; for most + subcommands, these are `packages.`*system*, + `legacyPackages.*system*` and the empty prefix. Thus, on + `x86_64-linux` `nix build nixpkgs#hello` will try to build the + attributes `packages.x86_64-linux.hello`, + `legacyPackages.x86_64-linux.hello` and `hello`. + +* **Store paths**: `/nix/store/v5sv61sszx301i0x6xysaqzla09nksnd-hello-2.10` + + These are paths inside the Nix store, or symlinks that resolve to a + path in the Nix store. + +* **Store derivations**: `/nix/store/p7gp6lxdg32h4ka1q398wd9r2zkbbz2v-hello-2.10.drv` + + Store derivations are store paths with extension `.drv` and are a + low-level representation of a build-time dependency graph used + internally by Nix. By default, if you pass a store derivation to a + `nix` subcommand, it will operate on the *output paths* of the + derivation. For example, `nix path-info` prints information about + the output paths: + + ```console + # nix path-info --json /nix/store/p7gp6lxdg32h4ka1q398wd9r2zkbbz2v-hello-2.10.drv + [{"path":"/nix/store/v5sv61sszx301i0x6xysaqzla09nksnd-hello-2.10",…}] + ``` + + If you want to operate on the store derivation itself, pass the + `--derivation` flag. + +* **Nix attributes**: `--file /path/to/nixpkgs hello` + + When the `-f` / `--file` *path* option is given, installables are + interpreted as attribute paths referencing a value returned by + evaluating the Nix file *path*. + +* **Nix expressions**: `--expr '(import <nixpkgs> {}).hello.overrideDerivation (prev: { name = "my-hello"; })'`. + + When the `--expr` option is given, all installables are interpreted + as Nix expressions. You may need to specify `--impure` if the + expression references impure inputs (such as `<nixpkgs>`). + +For most commands, if no installable is specified, the default is `.`, +i.e. Nix will operate on the default flake output attribute of the +flake in the current directory. + +# Nix stores + +Most `nix` subcommands operate on a *Nix store*. + +TODO: list store types, options + +)"" diff --git a/src/nix/optimise-store.cc b/src/nix/optimise-store.cc index bc7f175ac..985006e5a 100644 --- a/src/nix/optimise-store.cc +++ b/src/nix/optimise-store.cc @@ -13,14 +13,11 @@ struct CmdOptimiseStore : StoreCommand return "replace identical files in the store by hard links"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To optimise the Nix store:", - "nix store optimise" - }, - }; + return + #include "optimise-store.md" + ; } void run(ref<Store> store) override diff --git a/src/nix/optimise-store.md b/src/nix/optimise-store.md new file mode 100644 index 000000000..f6fb66f97 --- /dev/null +++ b/src/nix/optimise-store.md @@ -0,0 +1,23 @@ +R""( + +# Examples + +* Optimise the Nix store: + + ```console + nix store optimise + ``` + +# Description + +This command deduplicates the Nix store: it scans the store for +regular files with identical contents, and replaces them with hard +links to a single instance. + +Note that you can also set `auto-optimise-store` to `true` in +`nix.conf` to perform this optimisation incrementally whenever a new +path is added to the Nix store. To make this efficient, Nix maintains +a content-addressed index of all the files in the Nix store in the +directory `/nix/store/.links/`. + +)"" diff --git a/src/nix/path-info.cc b/src/nix/path-info.cc index 63cf885f9..30b6a50f8 100644 --- a/src/nix/path-info.cc +++ b/src/nix/path-info.cc @@ -29,38 +29,15 @@ struct CmdPathInfo : StorePathsCommand, MixJSON return "query information about store paths"; } - Category category() override { return catSecondary; } - - Examples examples() override + std::string doc() override { - return { - Example{ - "To show the closure sizes of every path in the current NixOS system closure, sorted by size:", - "nix path-info -rS /run/current-system | sort -nk2" - }, - Example{ - "To show a package's closure size and all its dependencies with human readable sizes:", - "nix path-info -rsSh nixpkgs#rust" - }, - Example{ - "To check the existence of a path in a binary cache:", - "nix path-info -r /nix/store/7qvk5c91...-geeqie-1.1 --store https://cache.nixos.org/" - }, - Example{ - "To print the 10 most recently added paths (using --json and the jq(1) command):", - "nix path-info --json --all | jq -r 'sort_by(.registrationTime)[-11:-1][].path'" - }, - Example{ - "To show the size of the entire Nix store:", - "nix path-info --json --all | jq 'map(.narSize) | add'" - }, - Example{ - "To show every path whose closure is bigger than 1 GB, sorted by closure size:", - "nix path-info --json --all -S | jq 'map(select(.closureSize > 1e9)) | sort_by(.closureSize) | map([.path, .closureSize])'" - }, - }; + return + #include "path-info.md" + ; } + Category category() override { return catSecondary; } + void printSize(uint64_t value) { if (!humanReadable) { diff --git a/src/nix/path-info.md b/src/nix/path-info.md new file mode 100644 index 000000000..76a83e39d --- /dev/null +++ b/src/nix/path-info.md @@ -0,0 +1,94 @@ +R""( + +# Examples + +* Print the store path produced by `nixpkgs#hello`: + + ```console + # nix path-info nixpkgs#hello + /nix/store/v5sv61sszx301i0x6xysaqzla09nksnd-hello-2.10 + ``` + +* Show the closure sizes of every path in the current NixOS system + closure, sorted by size: + + ```console + # nix path-info -rS /run/current-system | sort -nk2 + /nix/store/hl5xwp9kdrd1zkm0idm3kkby9q66z404-empty 96 + /nix/store/27324qvqhnxj3rncazmxc4mwy79kz8ha-nameservers 112 + … + /nix/store/539jkw9a8dyry7clcv60gk6na816j7y8-etc 5783255504 + /nix/store/zqamz3cz4dbzfihki2mk7a63mbkxz9xq-nixos-system-machine-20.09.20201112.3090c65 5887562256 + ``` + +* Show a package's closure size and all its dependencies with human + readable sizes: + + ```console + # nix path-info -rsSh nixpkgs#rustc + /nix/store/01rrgsg5zk3cds0xgdsq40zpk6g51dz9-ncurses-6.2-dev 386.7K 69.1M + /nix/store/0q783wnvixpqz6dxjp16nw296avgczam-libpfm-4.11.0 5.9M 37.4M + … + ``` + +* Check the existence of a path in a binary cache: + + ```console + # nix path-info -r /nix/store/blzxgyvrk32ki6xga10phr4sby2xf25q-geeqie-1.5.1 --store https://cache.nixos.org/ + path '/nix/store/blzxgyvrk32ki6xga10phr4sby2xf25q-geeqie-1.5.1' is not valid + + ``` + +* Print the 10 most recently added paths (using --json and the jq(1) + command): + + ```console + # nix path-info --json --all | jq -r 'sort_by(.registrationTime)[-11:-1][].path' + ``` + +* Show the size of the entire Nix store: + + ```console + # nix path-info --json --all | jq 'map(.narSize) | add' + 49812020936 + ``` + +* Show every path whose closure is bigger than 1 GB, sorted by closure + size: + + ```console + # nix path-info --json --all -S \ + | jq 'map(select(.closureSize > 1e9)) | sort_by(.closureSize) | map([.path, .closureSize])' + [ + …, + [ + "/nix/store/zqamz3cz4dbzfihki2mk7a63mbkxz9xq-nixos-system-machine-20.09.20201112.3090c65", + 5887562256 + ] + ] + ``` + +* Print the path of the store derivation produced by `nixpkgs#hello`: + + ```console + # nix path-info --derivation nixpkgs#hello + /nix/store/s6rn4jz1sin56rf4qj5b5v8jxjm32hlk-hello-2.10.drv + ``` + +# Description + +This command shows information about the store paths produced by +*installables*, or about all paths in the store if you pass `--all`. + +By default, this command only prints the store paths. You can get +additional information by passing flags such as `--closure-size`, +--size`, `--sigs` or `--json`. + +> **Warning** +> +> Note that `nix path-info` does not build or substitute the +> *installables* you specify. Thus, if the corresponding store paths +> don't already exist, this command will fail. You can use `nix build` +> to ensure that they exist. + +)"" diff --git a/src/nix/ping-store.cc b/src/nix/ping-store.cc index 19b1a55c8..62b645b06 100644 --- a/src/nix/ping-store.cc +++ b/src/nix/ping-store.cc @@ -8,17 +8,14 @@ struct CmdPingStore : StoreCommand { std::string description() override { - return "test whether a store can be opened"; + return "test whether a store can be accessed"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To test whether connecting to a remote Nix store via SSH works:", - "nix store ping --store ssh://mac1" - }, - }; + return + #include "ping-store.md" + ; } void run(ref<Store> store) override diff --git a/src/nix/ping-store.md b/src/nix/ping-store.md new file mode 100644 index 000000000..322093091 --- /dev/null +++ b/src/nix/ping-store.md @@ -0,0 +1,30 @@ +R""( + +# Examples + +* Test whether connecting to a remote Nix store via SSH works: + + ```console + # nix store ping --store ssh://mac1 + ``` + +* Test whether a URL is a valid binary cache: + + ```console + # nix store ping --store https://cache.nixos.org + ``` + +* Test whether the Nix daemon is up and running: + + ```console + # nix store ping --store daemon + ``` + +# Description + +This command tests whether a particular Nix store (specified by the +argument `--store` *url*) can be accessed. What this means is +dependent on the type of the store. For instance, for an SSH store it +means that Nix can connect to the specified machine. + +)"" diff --git a/src/nix/print-dev-env.md b/src/nix/print-dev-env.md new file mode 100644 index 000000000..b80252acf --- /dev/null +++ b/src/nix/print-dev-env.md @@ -0,0 +1,19 @@ +R""( + +# Examples + +* Apply the build environment of GNU hello to the current shell: + + ```console + # . <(nix print-dev-env nixpkgs#hello) + ``` + +# Description + +This command prints a shell script that can be sourced by `b`ash and +that sets the environment variables and shell functions defined by the +build process of *installable*. This allows you to get a similar build +environment in your current shell rather than in a subshell (as with +`nix develop`). + +)"" diff --git a/src/nix/profile-diff-closures.md b/src/nix/profile-diff-closures.md new file mode 100644 index 000000000..295d1252b --- /dev/null +++ b/src/nix/profile-diff-closures.md @@ -0,0 +1,28 @@ +R""( + +# Examples + +* Show what changed between each version of the NixOS system + profile: + + ```console + # nix profile diff-closures --profile /nix/var/nix/profiles/system + Version 13 -> 14: + acpi-call: 2020-04-07-5.8.13 → 2020-04-07-5.8.14 + aws-sdk-cpp: -6723.1 KiB + … + + Version 14 -> 15: + acpi-call: 2020-04-07-5.8.14 → 2020-04-07-5.8.16 + attica: -996.2 KiB + breeze-icons: -78713.5 KiB + brotli: 1.0.7 → 1.0.9, +44.2 KiB + ``` + +# Description + +This command shows the difference between the closures of subsequent +versions of a profile. See [`nix store +diff-closures`](nix3-store-diff-closures.md) for details. + +)"" diff --git a/src/nix/profile-info.md b/src/nix/profile-info.md new file mode 100644 index 000000000..a0c04fc8c --- /dev/null +++ b/src/nix/profile-info.md @@ -0,0 +1,31 @@ +R""( + +# Examples + +* Show what packages are installed in the default profile: + + ```console + # nix profile info + 0 flake:nixpkgs#legacyPackages.x86_64-linux.spotify github:NixOS/nixpkgs/c23db78bbd474c4d0c5c3c551877523b4a50db06#legacyPackages.x86_64-linux.spotify /nix/store/akpdsid105phbbvknjsdh7hl4v3fhjkr-spotify-1.1.46.916.g416cacf1 + 1 flake:nixpkgs#legacyPackages.x86_64-linux.zoom-us github:NixOS/nixpkgs/c23db78bbd474c4d0c5c3c551877523b4a50db06#legacyPackages.x86_64-linux.zoom-us /nix/store/89pmjmbih5qpi7accgacd17ybpgp4xfm-zoom-us-5.4.53350.1027 + 2 flake:blender-bin#defaultPackage.x86_64-linux github:edolstra/nix-warez/d09d7eea893dcb162e89bc67f6dc1ced14abfc27?dir=blender#defaultPackage.x86_64-linux /nix/store/zfgralhqjnam662kqsgq6isjw8lhrflz-blender-bin-2.91.0 + ``` + +# Description + +This command shows what packages are currently installed in a +profile. The output consists of one line per package, with the +following fields: + +* An integer that can be used to unambiguously identify the package in + invocations of `nix profile remove` and `nix profile upgrade`. + +* The original ("mutable") flake reference and output attribute path + used at installation time. + +* The immutable flake reference to which the mutable flake reference + was resolved. + +* The store path(s) of the package. + +)"" diff --git a/src/nix/profile-install.md b/src/nix/profile-install.md new file mode 100644 index 000000000..e3009491e --- /dev/null +++ b/src/nix/profile-install.md @@ -0,0 +1,27 @@ +R""( + +# Examples + +* Install a package from Nixpkgs: + + ```console + # nix profile install nixpkgs#hello + ``` + +* Install a package from a specific branch of Nixpkgs: + + ```console + # nix profile install nixpkgs/release-20.09#hello + ``` + +* Install a package from a specific revision of Nixpkgs: + + ```console + # nix profile install nixpkgs/d73407e8e6002646acfdef0e39ace088bacc83da#hello + ``` + +# Description + +This command adds *installables* to a Nix profile. + +)"" diff --git a/src/nix/profile-remove.md b/src/nix/profile-remove.md new file mode 100644 index 000000000..dcf825da9 --- /dev/null +++ b/src/nix/profile-remove.md @@ -0,0 +1,32 @@ +R""( + +# Examples + +* Remove a package by position: + + ```console + # nix profile remove 3 + ``` + +* Remove a package by attribute path: + + ```console + # nix profile remove packages.x86_64-linux.hello + ``` + +* Remove all packages: + ```console + # nix profile remove '.*' + ``` + +* Remove a package by store path: + + ```console + # nix profile remove /nix/store/rr3y0c6zyk7kjjl8y19s4lsrhn4aiq1z-hello-2.10 + ``` + +# Description + +This command removes a package from a profile. + +)"" diff --git a/src/nix/profile-upgrade.md b/src/nix/profile-upgrade.md new file mode 100644 index 000000000..2bd5d256d --- /dev/null +++ b/src/nix/profile-upgrade.md @@ -0,0 +1,41 @@ +R""( + +# Examples + +* Upgrade all packages that were installed using a mutable flake + reference: + + ```console + # nix profile upgrade '.*' + ``` + +* Upgrade a specific package: + + ```console + # nix profile upgrade packages.x86_64-linux.hello + ``` + +* Upgrade a specific profile element by number: + + ```console + # nix profile info + 0 flake:nixpkgs#legacyPackages.x86_64-linux.spotify … + + # nix profile upgrade 0 + ``` + +# Description + +This command upgrades a previously installed package in a Nix profile, +by fetching and evaluating the latest version of the flake from which +the package was installed. + +> **Warning** +> +> This only works if you used a *mutable* flake reference at +> installation time, e.g. `nixpkgs#hello`. It does not work if you +> used an *immutable* flake reference +> (e.g. `github:NixOS/nixpkgs/13d0c311e3ae923a00f734b43fd1d35b47d8943a#hello`), +> since in that case the "latest version" is always the same. + +)"" diff --git a/src/nix/profile.cc b/src/nix/profile.cc index 8cf5ccd62..d8d2b3a70 100644 --- a/src/nix/profile.cc +++ b/src/nix/profile.cc @@ -151,22 +151,11 @@ struct CmdProfileInstall : InstallablesCommand, MixDefaultProfile return "install a package into a profile"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To install a package from Nixpkgs:", - "nix profile install nixpkgs#hello" - }, - Example{ - "To install a package from a specific branch of Nixpkgs:", - "nix profile install nixpkgs/release-19.09#hello" - }, - Example{ - "To install a package from a specific revision of Nixpkgs:", - "nix profile install nixpkgs/1028bb33859f8dfad7f98e1c8d185f3d1aaa7340#hello" - }, - }; + return + #include "profile-install.md" + ; } void run(ref<Store> store) override @@ -257,26 +246,11 @@ struct CmdProfileRemove : virtual EvalCommand, MixDefaultProfile, MixProfileElem return "remove packages from a profile"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To remove a package by attribute path:", - "nix profile remove packages.x86_64-linux.hello" - }, - Example{ - "To remove all packages:", - "nix profile remove '.*'" - }, - Example{ - "To remove a package by store path:", - "nix profile remove /nix/store/rr3y0c6zyk7kjjl8y19s4lsrhn4aiq1z-hello-2.10" - }, - Example{ - "To remove a package by position:", - "nix profile remove 3" - }, - }; + return + #include "profile-remove.md" + ; } void run(ref<Store> store) override @@ -310,18 +284,11 @@ struct CmdProfileUpgrade : virtual SourceExprCommand, MixDefaultProfile, MixProf return "upgrade packages using their most recent flake"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To upgrade all packages that were installed using a mutable flake reference:", - "nix profile upgrade '.*'" - }, - Example{ - "To upgrade a specific package:", - "nix profile upgrade packages.x86_64-linux.hello" - }, - }; + return + #include "profile-upgrade.md" + ; } void run(ref<Store> store) override @@ -377,14 +344,11 @@ struct CmdProfileInfo : virtual EvalCommand, virtual StoreCommand, MixDefaultPro return "list installed packages"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To show what packages are installed in the default profile:", - "nix profile info" - }, - }; + return + #include "profile-info.md" + ; } void run(ref<Store> store) override @@ -405,17 +369,14 @@ struct CmdProfileDiffClosures : virtual StoreCommand, MixDefaultProfile { std::string description() override { - return "show the closure difference between each generation of a profile"; + return "show the closure difference between each version of a profile"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To show what changed between each generation of the NixOS system profile:", - "nix profile diff-closures --profile /nix/var/nix/profiles/system" - }, - }; + return + #include "profile-diff-closures.md" + ; } void run(ref<Store> store) override @@ -429,7 +390,7 @@ struct CmdProfileDiffClosures : virtual StoreCommand, MixDefaultProfile if (prevGen) { if (!first) std::cout << "\n"; first = false; - std::cout << fmt("Generation %d -> %d:\n", prevGen->number, gen.number); + std::cout << fmt("Version %d -> %d:\n", prevGen->number, gen.number); printClosureDiff(store, store->followLinksToStorePath(prevGen->path), store->followLinksToStorePath(gen.path), @@ -458,6 +419,13 @@ struct CmdProfile : NixMultiCommand return "manage Nix profiles"; } + std::string doc() override + { + return + #include "profile.md" + ; + } + void run() override { if (!command) diff --git a/src/nix/profile.md b/src/nix/profile.md new file mode 100644 index 000000000..d3ddcd3d1 --- /dev/null +++ b/src/nix/profile.md @@ -0,0 +1,107 @@ +R""( + +# Description + +`nix profile` allows you to create and manage *Nix profiles*. A Nix +profile is a set of packages that can be installed and upgraded +independently from each other. Nix profiles are versioned, allowing +them to be rolled back easily. + +# Default profile + +The default profile used by `nix profile` is `$HOME/.nix-profile`, +which, if it does not exist, is created as a symlink to +`/nix/var/nix/profiles/per-user/default` if Nix is invoked by the +`root` user, or `/nix/var/nix/profiles/per-user/`*username* otherwise. + +You can specify another profile location using `--profile` *path*. + +# Filesystem layout + +Profiles are versioned as follows. When using profile *path*, *path* +is a symlink to *path*`-`*N*, where *N* is the current *version* of +the profile. In turn, *path*`-`*N* is a symlink to a path in the Nix +store. For example: + +```console +$ ls -l /nix/var/nix/profiles/per-user/alice/profile* +lrwxrwxrwx 1 alice users 14 Nov 25 14:35 /nix/var/nix/profiles/per-user/alice/profile -> profile-7-link +lrwxrwxrwx 1 alice users 51 Oct 28 16:18 /nix/var/nix/profiles/per-user/alice/profile-5-link -> /nix/store/q69xad13ghpf7ir87h0b2gd28lafjj1j-profile +lrwxrwxrwx 1 alice users 51 Oct 29 13:20 /nix/var/nix/profiles/per-user/alice/profile-6-link -> /nix/store/6bvhpysd7vwz7k3b0pndn7ifi5xr32dg-profile +lrwxrwxrwx 1 alice users 51 Nov 25 14:35 /nix/var/nix/profiles/per-user/alice/profile-7-link -> /nix/store/mp0x6xnsg0b8qhswy6riqvimai4gm677-profile +``` + +Each of these symlinks is a root for the Nix garbage collector. + +The contents of the store path corresponding to each version of the +profile is a tree of symlinks to the files of the installed packages, +e.g. + +```console +$ ll -R /nix/var/nix/profiles/per-user/eelco/profile-7-link/ +/nix/var/nix/profiles/per-user/eelco/profile-7-link/: +total 20 +dr-xr-xr-x 2 root root 4096 Jan 1 1970 bin +-r--r--r-- 2 root root 1402 Jan 1 1970 manifest.json +dr-xr-xr-x 4 root root 4096 Jan 1 1970 share + +/nix/var/nix/profiles/per-user/eelco/profile-7-link/bin: +total 20 +lrwxrwxrwx 5 root root 79 Jan 1 1970 chromium -> /nix/store/ijm5k0zqisvkdwjkc77mb9qzb35xfi4m-chromium-86.0.4240.111/bin/chromium +lrwxrwxrwx 7 root root 87 Jan 1 1970 spotify -> /nix/store/w9182874m1bl56smps3m5zjj36jhp3rn-spotify-1.1.26.501.gbe11e53b-15/bin/spotify +lrwxrwxrwx 3 root root 79 Jan 1 1970 zoom-us -> /nix/store/wbhg2ga8f3h87s9h5k0slxk0m81m4cxl-zoom-us-5.3.469451.0927/bin/zoom-us + +/nix/var/nix/profiles/per-user/eelco/profile-7-link/share/applications: +total 12 +lrwxrwxrwx 4 root root 120 Jan 1 1970 chromium-browser.desktop -> /nix/store/4cf803y4vzfm3gyk3vzhzb2327v0kl8a-chromium-unwrapped-86.0.4240.111/share/applications/chromium-browser.desktop +lrwxrwxrwx 7 root root 110 Jan 1 1970 spotify.desktop -> /nix/store/w9182874m1bl56smps3m5zjj36jhp3rn-spotify-1.1.26.501.gbe11e53b-15/share/applications/spotify.desktop +lrwxrwxrwx 3 root root 107 Jan 1 1970 us.zoom.Zoom.desktop -> /nix/store/wbhg2ga8f3h87s9h5k0slxk0m81m4cxl-zoom-us-5.3.469451.0927/share/applications/us.zoom.Zoom.desktop + +… +``` + +The file `manifest.json` records the provenance of the packages that +are installed in this version of the profile. It looks like this: + +```json +{ + "version": 1, + "elements": [ + { + "active": true, + "attrPath": "legacyPackages.x86_64-linux.zoom-us", + "originalUri": "flake:nixpkgs", + "storePaths": [ + "/nix/store/wbhg2ga8f3h87s9h5k0slxk0m81m4cxl-zoom-us-5.3.469451.0927" + ], + "uri": "github:NixOS/nixpkgs/13d0c311e3ae923a00f734b43fd1d35b47d8943a" + }, + … + ] +} +``` + +Each object in the array `elements` denotes an installed package and +has the following fields: + +* `originalUri`: The [flake reference](./nix3-flake.md) specified by + the user at the time of installation (e.g. `nixpkgs`). This is also + the flake reference that will be used by `nix profile upgrade`. + +* `uri`: The immutable flake reference to which `originalUri` + resolved. + +* `attrPath`: The flake output attribute that provided this + package. Note that this is not necessarily the attribute that the + user specified, but the one resulting from applying the default + attribute paths and prefixes; for instance, `hello` might resolve to + `packages.x86_64-linux.hello` and the empty string to + `defaultPackage.x86_64-linux`. + +* `storePath`: The paths in the Nix store containing the package. + +* `active`: Whether the profile contains symlinks to the files of this + package. If set to false, the package is kept in the Nix store, but + is not "visible" in the profile's symlink tree. + +)"" diff --git a/src/nix/registry-add.md b/src/nix/registry-add.md new file mode 100644 index 000000000..80a31996a --- /dev/null +++ b/src/nix/registry-add.md @@ -0,0 +1,33 @@ +R""( + +# Examples + +* Set the `nixpkgs` flake identifier to a specific branch of Nixpkgs: + + ```console + # nix registry add nixpkgs github:NixOS/nixpkgs/nixos-20.03 + ``` + +* Pin `nixpkgs` to a specific revision: + + ```console + # nix registry add nixpkgs github:NixOS/nixpkgs/925b70cd964ceaedee26fde9b19cc4c4f081196a + ``` + +* Add an entry that redirects a specific branch of `nixpkgs` to + another fork: + + ```console + # nix registry add nixpkgs/nixos-20.03 ~/Dev/nixpkgs + ``` + +# Description + +This command adds an entry to the user registry that maps flake +reference *from-url* to flake reference *to-url*. If an entry for +*from-url* already exists, it is overwritten. + +Entries can be removed using [`nix registry +remove`](./nix3-registry-remove.md). + +)"" diff --git a/src/nix/registry-list.md b/src/nix/registry-list.md new file mode 100644 index 000000000..30b6e29d8 --- /dev/null +++ b/src/nix/registry-list.md @@ -0,0 +1,29 @@ +R""( + +# Examples + +* Show the contents of all registries: + + ```console + # nix registry list + user flake:dwarffs github:edolstra/dwarffs/d181d714fd36eb06f4992a1997cd5601e26db8f5 + system flake:nixpkgs path:/nix/store/fxl9mrm5xvzam0lxi9ygdmksskx4qq8s-source?lastModified=1605220118&narHash=sha256-Und10ixH1WuW0XHYMxxuHRohKYb45R%2fT8CwZuLd2D2Q=&rev=3090c65041104931adda7625d37fa874b2b5c124 + global flake:blender-bin github:edolstra/nix-warez?dir=blender + global flake:dwarffs github:edolstra/dwarffs + … + ``` + +# Description + +This command displays the contents of all registries on standard +output. Each line represents one registry entry in the format *type* +*from* *to*, where *type* denotes the registry containing the entry: + +* `flags`: entries specified on the command line using `--override-flake`. +* `user`: the user registry. +* `system`: the system registry. +* `global`: the global registry. + +See the [`nix registry` manual page](./nix3-registry.md) for more details. + +)"" diff --git a/src/nix/registry-pin.md b/src/nix/registry-pin.md new file mode 100644 index 000000000..6e97e003e --- /dev/null +++ b/src/nix/registry-pin.md @@ -0,0 +1,38 @@ +R""( + +# Examples + +* Pin `nixpkgs` to its most recent Git revision: + + ```console + # nix registry pin nixpkgs + ``` + + Afterwards the user registry will have an entry like this: + + ```console + nix registry list | grep '^user ' + user flake:nixpkgs github:NixOS/nixpkgs/925b70cd964ceaedee26fde9b19cc4c4f081196a + ``` + + and `nix flake info` will say: + + ```console + # nix flake info nixpkgs + Resolved URL: github:NixOS/nixpkgs/925b70cd964ceaedee26fde9b19cc4c4f081196a + Locked URL: github:NixOS/nixpkgs/925b70cd964ceaedee26fde9b19cc4c4f081196a + … + ``` + +# Description + +This command adds an entry to the user registry that maps flake +reference *url* to the corresponding *locked* flake reference, that +is, a flake reference that specifies an exact revision or content +hash. This ensures that until this registry entry is removed, all uses +of *url* will resolve to exactly the same flake. + +Entries can be removed using [`nix registry +remove`](./nix3-registry-remove.md). + +)"" diff --git a/src/nix/registry-remove.md b/src/nix/registry-remove.md new file mode 100644 index 000000000..4c0eb4947 --- /dev/null +++ b/src/nix/registry-remove.md @@ -0,0 +1,16 @@ +R""( + +# Examples + +* Remove the entry `nixpkgs` from the user registry: + + ```console + # nix registry remove nixpkgs + ``` + +# Description + +This command removes from the user registry any entry for flake +reference *url*. + +)"" diff --git a/src/nix/registry.cc b/src/nix/registry.cc index 9352e00a7..f9719600f 100644 --- a/src/nix/registry.cc +++ b/src/nix/registry.cc @@ -17,6 +17,13 @@ struct CmdRegistryList : StoreCommand return "list available Nix flakes"; } + std::string doc() override + { + return + #include "registry-list.md" + ; + } + void run(nix::ref<nix::Store> store) override { using namespace fetchers; @@ -47,6 +54,13 @@ struct CmdRegistryAdd : MixEvalArgs, Command return "add/replace flake in user flake registry"; } + std::string doc() override + { + return + #include "registry-add.md" + ; + } + CmdRegistryAdd() { expectArg("from-url", &fromUrl); @@ -75,6 +89,13 @@ struct CmdRegistryRemove : virtual Args, MixEvalArgs, Command return "remove flake from user flake registry"; } + std::string doc() override + { + return + #include "registry-remove.md" + ; + } + CmdRegistryRemove() { expectArg("url", &url); @@ -97,6 +118,13 @@ struct CmdRegistryPin : virtual Args, EvalCommand return "pin a flake to its current version in user flake registry"; } + std::string doc() override + { + return + #include "registry-pin.md" + ; + } + CmdRegistryPin() { expectArg("url", &url); @@ -132,6 +160,13 @@ struct CmdRegistry : virtual NixMultiCommand return "manage the flake registry"; } + std::string doc() override + { + return + #include "registry.md" + ; + } + Category category() override { return catSecondary; } void run() override diff --git a/src/nix/registry.md b/src/nix/registry.md new file mode 100644 index 000000000..557e5795b --- /dev/null +++ b/src/nix/registry.md @@ -0,0 +1,98 @@ +R""( + +# Description + +`nix flake` provides subcommands for managing *flake +registries*. Flake registries are a convenience feature that allows +you to refer to flakes using symbolic identifiers such as `nixpkgs`, +rather than full URLs such as `git://github.com/NixOS/nixpkgs`. You +can use these identifiers on the command line (e.g. when you do `nix +run nixpkgs#hello`) or in flake input specifications in `flake.nix` +files. The latter are automatically resolved to full URLs and recorded +in the flake's `flake.lock` file. + +In addition, the flake registry allows you to redirect arbitrary flake +references (e.g. `github:NixOS/patchelf`) to another location, such as +a local fork. + +There are multiple registries. These are, in order from lowest to +highest precedence: + +* The global registry, which is a file downloaded from the URL + specified by the setting `flake-registry`. It is cached locally and + updated automatically when it's older than `tarball-ttl` + seconds. The default global registry is kept in [a GitHub + repository](https://github.com/NixOS/flake-registry). + +* The system registry, which is shared by all users. The default + location is `/etc/nix/registry.json`. On NixOS, the system registry + can be specified using the NixOS option `nix.registry`. + +* The user registry `~/.config/nix/registry.json`. This registry can + be modified by commands such as `nix flake pin`. + +* Overrides specified on the command line using the option + `--override-flake`. + +# Registry format + +A registry is a JSON file with the following format: + +```json +{ + "version": 2, + [ + { + "from": { + "type": "indirect", + "id": "nixpkgs" + }, + "to": { + "type": "github", + "owner": "NixOS", + "repo": "nixpkgs" + } + }, + ... + ] +} +``` + +That is, it contains a list of objects with attributes `from` and +`to`, both of which contain a flake reference in attribute +representation. (For example, `{"type": "indirect", "id": "nixpkgs"}` +is the attribute representation of `nixpkgs`, while `{"type": +"github", "owner": "NixOS", "repo": "nixpkgs"}` is the attribute +representation of `github:NixOS/nixpkgs`.) + +Given some flake reference *R*, a registry entry is used if its +`from` flake reference *matches* *R*. *R* is then replaced by the +*unification* of the `to` flake reference with *R*. + +# Matching + +The `from` flake reference in a registry entry *matches* some flake +reference *R* if the attributes in `from` are the same as the +attributes in `R`. For example: + +* `nixpkgs` matches with `nixpkgs`. + +* `nixpkgs` matches with `nixpkgs/nixos-20.09`. + +* `nixpkgs/nixos-20.09` does not match with `nixpkgs`. + +* `nixpkgs` does not match with `git://github.com/NixOS/patchelf`. + +# Unification + +The `to` flake reference in a registry entry is *unified* with some flake +reference *R* by taking `to` and applying the `rev` and `ref` +attributes from *R*, if specified. For example: + +* `github:NixOS/nixpkgs` unified with `nixpkgs` produces `github:NixOS/nixpkgs`. + +* `github:NixOS/nixpkgs` unified with `nixpkgs/nixos-20.09` produces `github:NixOS/nixpkgs/nixos-20.09`. + +* `github:NixOS/nixpkgs/master` unified with `nixpkgs/nixos-20.09` produces `github:NixOS/nixpkgs/nixos-20.09`. + +)"" diff --git a/src/nix/repl.cc b/src/nix/repl.cc index a992d8732..bce8d31dc 100644 --- a/src/nix/repl.cc +++ b/src/nix/repl.cc @@ -405,6 +405,7 @@ bool NixRepl::processLine(string line) } if (command == ":?" || command == ":help") { + // FIXME: convert to Markdown, include in the 'nix repl' manpage. std::cout << "The following commands are available:\n" << "\n" @@ -801,14 +802,11 @@ struct CmdRepl : StoreCommand, MixEvalArgs return "start an interactive environment for evaluating Nix expressions"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "Display all special commands within the REPL:", - "nix repl\nnix-repl> :?" - } - }; + return + #include "repl.md" + ; } void run(ref<Store> store) override diff --git a/src/nix/repl.md b/src/nix/repl.md new file mode 100644 index 000000000..bba60f871 --- /dev/null +++ b/src/nix/repl.md @@ -0,0 +1,57 @@ +R""( + +# Examples + +* Display all special commands within the REPL: + + ```console + # nix repl + nix-repl> :? + ``` + +* Evaluate some simple Nix expressions: + + ```console + # nix repl + + nix-repl> 1 + 2 + 3 + + nix-repl> map (x: x * 2) [1 2 3] + [ 2 4 6 ] + ``` + +* Interact with Nixpkgs in the REPL: + + ```console + # nix repl '<nixpkgs>' + + Loading '<nixpkgs>'... + Added 12428 variables. + + nix-repl> emacs.name + "emacs-27.1" + + nix-repl> emacs.drvPath + "/nix/store/lp0sjrhgg03y2n0l10n70rg0k7hhyz0l-emacs-27.1.drv" + + nix-repl> drv = runCommand "hello" { buildInputs = [ hello ]; } "hello > $out" + + nix-repl> :b x + this derivation produced the following outputs: + out -> /nix/store/0njwbgwmkwls0w5dv9mpc1pq5fj39q0l-hello + + nix-repl> builtins.readFile drv + "Hello, world!\n" + ``` + +# Description + +This command provides an interactive environment for evaluating Nix +expressions. (REPL stands for 'read–eval–print loop'.) + +On startup, it loads the Nix expressions named *files* and adds them +into the lexical scope. You can load addition files using the `:l +<filename>` command, or reload all files using `:r`. + +)"" diff --git a/src/nix/run.cc b/src/nix/run.cc index ec61fc79a..1340dd46f 100644 --- a/src/nix/run.cc +++ b/src/nix/run.cc @@ -86,26 +86,11 @@ struct CmdShell : InstallablesCommand, RunCommon, MixEnvironment return "run a shell in which the specified packages are available"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To start a shell providing GNU Hello from NixOS 20.03:", - "nix shell nixpkgs/nixos-20.03#hello" - }, - Example{ - "To start a shell providing youtube-dl from your 'nixpkgs' channel:", - "nix shell nixpkgs#youtube-dl" - }, - Example{ - "To run GNU Hello:", - "nix shell nixpkgs#hello -c hello --greeting 'Hi everybody!'" - }, - Example{ - "To run GNU Hello in a chroot store:", - "nix shell --store ~/my-nix nixpkgs#hello -c hello" - }, - }; + return + #include "shell.md" + ; } void run(ref<Store> store) override @@ -168,22 +153,11 @@ struct CmdRun : InstallableCommand, RunCommon return "run a Nix application"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To run Blender:", - "nix run blender-bin" - }, - Example{ - "To run vim from nixpkgs:", - "nix run nixpkgs#vim" - }, - Example{ - "To run vim from nixpkgs with arguments:", - "nix run nixpkgs#vim -- --help" - }, - }; + return + #include "run.md" + ; } Strings getDefaultFlakeAttrPaths() override diff --git a/src/nix/run.md b/src/nix/run.md new file mode 100644 index 000000000..c178e8b13 --- /dev/null +++ b/src/nix/run.md @@ -0,0 +1,87 @@ +R""( + +# Examples + +* Run the default app from the `blender-bin` flake: + + ```console + # nix run blender-bin + ``` + +* Run a non-default app from the `blender-bin` flake: + + ```console + # nix run blender-bin#blender_2_83 + ``` + + Tip: you can find apps provided by this flake by running `nix flake + show blender-bin`. + +* Run `vim` from the `nixpkgs` flake: + + ```console + # nix run nixpkgs#vim + ``` + + Note that `vim` (as of the time of writing of this page) is not an + app but a package. Thus, Nix runs the eponymous file from the `vim` + package. + +* Run `vim` with arguments: + + ```console + # nix run nixpkgs#vim -- --help + ``` + +# Description + +`nix run` builds and runs *installable*, which must evaluate to an +*app* or a regular Nix derivation. + +If *installable* evaluates to an *app* (see below), it executes the +program specified by the app definition. + +If *installable* evaluates to a derivation, it will try to execute the +program `<out>/bin/<name>`, where *out* is the primary output store +path of the derivation and *name* is the name part of the value of the +`name` attribute of the derivation (e.g. if `name` is set to +`hello-1.10`, it will run `$out/bin/hello`). + +# Flake output attributes + +If no flake output attribute is given, `nix run` tries the following +flake output attributes: + +* `defaultApp.<system>` + +* `defaultPackage.<system>` + +If an attribute *name* is given, `nix run` tries the following flake +output attributes: + +* `apps.<system>.<name>` + +* `packages.<system>.<name>` + +* `legacyPackages.<system>.<name>` + +# Apps + +An app is specified by a flake output attribute named +`apps.<system>.<name>` or `defaultApp.<system>`. It looks like this: + +```nix +apps.x86_64-linux.blender_2_79 = { + type = "app"; + program = "${self.packages.x86_64-linux.blender_2_79}/bin/blender"; +}; +``` + +The only supported attributes are: + +* `type` (required): Must be set to `app`. + +* `program` (required): The full path of the executable to run. It + must reside in the Nix store. + +)"" diff --git a/src/nix/search.cc b/src/nix/search.cc index 47770e128..9f864b3a4 100644 --- a/src/nix/search.cc +++ b/src/nix/search.cc @@ -41,29 +41,14 @@ struct CmdSearch : InstallableCommand, MixJSON std::string description() override { - return "query available packages"; + return "search for packages"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To show all packages in the flake in the current directory:", - "nix search" - }, - Example{ - "To show packages in the 'nixpkgs' flake containing 'blender' in its name or description:", - "nix search nixpkgs blender" - }, - Example{ - "To search for Firefox or Chromium:", - "nix search nixpkgs 'firefox|chromium'" - }, - Example{ - "To search for packages containing 'git' and either 'frontend' or 'gui':", - "nix search nixpkgs git 'frontend|gui'" - } - }; + return + #include "search.md" + ; } Strings getDefaultFlakeAttrPaths() override diff --git a/src/nix/search.md b/src/nix/search.md new file mode 100644 index 000000000..d182788a6 --- /dev/null +++ b/src/nix/search.md @@ -0,0 +1,72 @@ +R""( + +# Examples + +* Show all packages in the `nixpkgs` flake: + + ```console + # nix search nixpkgs + * legacyPackages.x86_64-linux.AMB-plugins (0.8.1) + A set of ambisonics ladspa plugins + + * legacyPackages.x86_64-linux.ArchiSteamFarm (4.3.1.0) + Application with primary purpose of idling Steam cards from multiple accounts simultaneously + … + ``` + +* Show packages in the `nixpkgs` flake containing `blender` in its + name or description: + + ```console + # nix search nixpkgs blender + * legacyPackages.x86_64-linux.blender (2.91.0) + 3D Creation/Animation/Publishing System + ``` + +* Search for packages underneath the attribute `gnome3` in Nixpkgs: + + ```console + # nix search nixpkgs#gnome3 vala + * legacyPackages.x86_64-linux.gnome3.vala (0.48.9) + Compiler for GObject type system + ``` + +* Show all packages in the flake in the current directory: + + ```console + # nix search + ``` + +* Search for Firefox or Chromium: + + ```console + # nix search nixpkgs 'firefox|chromium' + ``` + +* Search for packages containing `git'`and either `frontend` or `gui`: + + ```console + # nix search nixpkgs git 'frontend|gui' + ``` + +# Description + +`nix search` searches *installable* (which must be evaluatable, e.g. a +flake) for packages whose name or description matches all of the +regular expressions *regex*. For each matching package, It prints the +full attribute name (from the root of the installable), the version +and the `meta.description` field, highlighting the substrings that +were matched by the regular expressions. If no regular expressions are +specified, all packages are shown. + +# Flake output attributes + +If no flake output attribute is given, `nix search` searches for +packages: + +* Directly underneath `packages.<system>`. + +* Underneath `legacyPackages.<system>`, recursing into attribute sets + that contain an attribute `recurseForDerivations = true`. + +)"" diff --git a/src/nix/shell.md b/src/nix/shell.md new file mode 100644 index 000000000..2a379e03f --- /dev/null +++ b/src/nix/shell.md @@ -0,0 +1,48 @@ +R""( + +# Examples + +* Start a shell providing `youtube-dl` from the `nixpkgs` flake: + + ```console + # nix shell nixpkgs#youtube-dl + # youtube-dl --version + 2020.11.01.1 + ``` + +* Start a shell providing GNU Hello from NixOS 20.03: + + ```console + # nix shell nixpkgs/nixos-20.03#hello + ``` + +* Run GNU Hello: + + ```console + # nix shell nixpkgs#hello -c hello --greeting 'Hi everybody!' + Hi everybody! + ``` + +* Run GNU Hello in a chroot store: + + ```console + # nix shell --store ~/my-nix nixpkgs#hello -c hello + ``` + +* Start a shell providing GNU Hello in a chroot store: + + ```console + # nix shell --store ~/my-nix nixpkgs#hello nixpkgs#bashInteractive -c bash + ``` + + Note that it's necessary to specify `bash` explicitly because your + default shell (e.g. `/bin/bash`) generally will not exist in the + chroot. + +# Description + +`nix shell` runs a command in an environment in which the `$PATH` +variable provides the specified *installables*. If not command is +specified, it starts the default shell of your user account. + +)"" diff --git a/src/nix/show-derivation.cc b/src/nix/show-derivation.cc index 8e1a58ac2..13f2c8e69 100644 --- a/src/nix/show-derivation.cc +++ b/src/nix/show-derivation.cc @@ -29,18 +29,11 @@ struct CmdShowDerivation : InstallablesCommand return "show the contents of a store derivation"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To show the store derivation that results from evaluating the Hello package:", - "nix show-derivation nixpkgs#hello" - }, - Example{ - "To show the full derivation graph (if available) that produced your NixOS system:", - "nix show-derivation -r /run/current-system" - }, - }; + return + #include "show-derivation.md" + ; } Category category() override { return catUtility; } @@ -103,7 +96,7 @@ struct CmdShowDerivation : InstallablesCommand } } - drvObj.attr("platform", drv.platform); + drvObj.attr("system", drv.platform); drvObj.attr("builder", drv.builder); { diff --git a/src/nix/show-derivation.md b/src/nix/show-derivation.md new file mode 100644 index 000000000..aa863899c --- /dev/null +++ b/src/nix/show-derivation.md @@ -0,0 +1,103 @@ +R""( + +# Examples + +* Show the store derivation that results from evaluating the Hello + package: + + ```console + # nix show-derivation nixpkgs#hello + { + "/nix/store/s6rn4jz1sin56rf4qj5b5v8jxjm32hlk-hello-2.10.drv": { + … + } + } + ``` + +* Show the full derivation graph (if available) that produced your + NixOS system: + + ```console + # nix show-derivation -r /run/current-system + ``` + +* Print all files fetched using `fetchurl` by Firefox's dependency + graph: + + ```console + # nix show-derivation -r nixpkgs#firefox \ + | jq -r '.[] | select(.outputs.out.hash and .env.urls) | .env.urls' \ + | uniq | sort + ``` + + Note that `.outputs.out.hash` selects *fixed-output derivations* + (derivations that produce output with a specified content hash), + while `.env.urls` selects derivations with a `urls` attribute. + +# Description + +This command prints on standard output a JSON representation of the +store derivations to which *installables* evaluate. Store derivations +are used internally by Nix. They are store paths with extension `.drv` +that represent the build-time dependency graph to which a Nix +expression evaluates. + +By default, this command only shows top-level derivations, but with +`--recursive`, it also shows their dependencies. + +The JSON output is a JSON object whose keys are the store paths of the +derivations, and whose values are a JSON object with the following +fields: + +* `outputs`: Information about the output paths of the + derivation. This is a JSON object with one member per output, where + the key is the output name and the value is a JSON object with these + fields: + + * `path`: The output path. + * `hashAlgo`: For fixed-output derivations, the hashing algorithm + (e.g. `sha256`), optionally prefixed by `r:` if `hash` denotes a + NAR hash rather than a flat file hash. + * `hash`: For fixed-output derivations, the expected content hash in + base-16. + + Example: + + ```json + "outputs": { + "out": { + "path": "/nix/store/2543j7c6jn75blc3drf4g5vhb1rhdq29-source", + "hashAlgo": "r:sha256", + "hash": "6fc80dcc62179dbc12fc0b5881275898f93444833d21b89dfe5f7fbcbb1d0d62" + } + } + ``` + +* `inputSrcs`: A list of store paths on which this derivation depends. + +* `inputDrvs`: A JSON object specifying the derivations on which this + derivation depends, and what outputs of those derivations. For + example, + + ```json + "inputDrvs": { + "/nix/store/6lkh5yi7nlb7l6dr8fljlli5zfd9hq58-curl-7.73.0.drv": ["dev"], + "/nix/store/fn3kgnfzl5dzym26j8g907gq3kbm8bfh-unzip-6.0.drv": ["out"] + } + ``` + + specifies that this derivation depends on the `dev` output of + `curl`, and the `out` output of `unzip`. + +* `system`: The system type on which this derivation is to be built + (e.g. `x86_64-linux`). + +* `builder`: The absolute path of the program to be executed to run + the build. Typically this is the `bash` shell + (e.g. `/nix/store/r3j288vpmczbl500w6zz89gyfa4nr0b1-bash-4.4-p23/bin/bash`). + +* `args`: The command-line arguments passed to the `builder`. + +* `env`: The environment passed to the `builder`. + +)"" diff --git a/src/nix/store-cat.md b/src/nix/store-cat.md new file mode 100644 index 000000000..da2073473 --- /dev/null +++ b/src/nix/store-cat.md @@ -0,0 +1,19 @@ +R""( + +# Examples + +* Show the contents of a file in a binary cache: + + ```console + # nix store cat --store https://cache.nixos.org/ \ + /nix/store/0i2jd68mp5g6h2sa5k9c85rb80sn8hi9-hello-2.10/bin/hello | hexdump -C | head -n1 + 00000000 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 |.ELF............| + ``` + +# Description + +This command prints on standard output the contents of the regular +file *path* in a Nix store. *path* can be a top-level store path or +any file inside a store path. + +)"" diff --git a/src/nix/store-dump-path.md b/src/nix/store-dump-path.md new file mode 100644 index 000000000..4ef563526 --- /dev/null +++ b/src/nix/store-dump-path.md @@ -0,0 +1,23 @@ +R""( + +# Examples + +* To get a NAR containing the GNU Hello package: + + ```console + # nix store dump-path nixpkgs#hello > hello.nar + ``` + +* To get a NAR from the binary cache https://cache.nixos.org/: + + ```console + # nix store dump-path --store https://cache.nixos.org/ \ + /nix/store/7crrmih8c52r8fbnqb933dxrsp44md93-glibc-2.25 > glibc.nar + ``` + +# Description + +This command generates a NAR file containing the serialisation of the +store path *installable*. The NAR is written to standard output. + +)"" diff --git a/src/nix/store-ls.md b/src/nix/store-ls.md new file mode 100644 index 000000000..836efce42 --- /dev/null +++ b/src/nix/store-ls.md @@ -0,0 +1,27 @@ +R""( + +# Examples + +* To list the contents of a store path in a binary cache: + + ```console + # nix store ls --store https://cache.nixos.org/ -lR /nix/store/0i2jd68mp5g6h2sa5k9c85rb80sn8hi9-hello-2.10 + dr-xr-xr-x 0 ./bin + -r-xr-xr-x 38184 ./bin/hello + dr-xr-xr-x 0 ./share + … + ``` + +* To show information about a specific file in a binary cache: + + ```console + # nix store ls --store https://cache.nixos.org/ -l /nix/store/0i2jd68mp5g6h2sa5k9c85rb80sn8hi9-hello-2.10/bin/hello + -r-xr-xr-x 38184 hello + ``` + +# Description + +This command shows information about *path* in a Nix store. *path* can +be a top-level store path or any file inside a store path. + +)"" diff --git a/src/nix/upgrade-nix.cc b/src/nix/upgrade-nix.cc index 66ecc5b34..79be31e73 100644 --- a/src/nix/upgrade-nix.cc +++ b/src/nix/upgrade-nix.cc @@ -37,18 +37,11 @@ struct CmdUpgradeNix : MixDryRun, StoreCommand return "upgrade Nix to the latest stable version"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To upgrade Nix to the latest stable version:", - "nix upgrade-nix" - }, - Example{ - "To upgrade Nix in a specific profile:", - "nix upgrade-nix -p /nix/var/nix/profiles/per-user/alice/profile" - }, - }; + return + #include "upgrade-nix.md" + ; } Category category() override { return catNixInstallation; } diff --git a/src/nix/upgrade-nix.md b/src/nix/upgrade-nix.md new file mode 100644 index 000000000..4d27daad9 --- /dev/null +++ b/src/nix/upgrade-nix.md @@ -0,0 +1,28 @@ +R""( + +# Examples + +* Upgrade Nix to the latest stable version: + + ```console + # nix upgrade-nix + ``` + +* Upgrade Nix in a specific profile: + + ```console + # nix upgrade-nix -p /nix/var/nix/profiles/per-user/alice/profile + ``` + +# Description + +This command upgrades Nix to the latest version. By default, it +locates the directory containing the `nix` binary in the `$PATH` +environment variable. If that directory is a Nix profile, it will +upgrade the `nix` package in that profile to the latest stable binary +release. + +You cannot use this command to upgrade Nix in the system profile of a +NixOS system (that is, if `nix` is found in `/run/current-system`). + +)"" diff --git a/src/nix/verify.cc b/src/nix/verify.cc index bcf85d7dd..16d42349f 100644 --- a/src/nix/verify.cc +++ b/src/nix/verify.cc @@ -35,18 +35,11 @@ struct CmdVerify : StorePathsCommand return "verify the integrity of store paths"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To verify the entire Nix store:", - "nix store verify --all" - }, - Example{ - "To check whether each path in the closure of Firefox has at least 2 signatures:", - "nix store verify -r -n2 --no-contents $(type -p firefox)" - }, - }; + return + #include "verify.md" + ; } void run(ref<Store> store, StorePaths storePaths) override diff --git a/src/nix/verify.md b/src/nix/verify.md new file mode 100644 index 000000000..1c43792e7 --- /dev/null +++ b/src/nix/verify.md @@ -0,0 +1,49 @@ +R""( + +# Examples + +* Verify the entire Nix store: + + ```console + # nix store verify --all + ``` + +* Check whether each path in the closure of Firefox has at least 2 + signatures: + + ```console + # nix store verify -r -n2 --no-contents $(type -p firefox) + ``` + +* Verify a store path in the binary cache `https://cache.nixos.org/`: + + ```console + # nix store verify --store https://cache.nixos.org/ \ + /nix/store/v5sv61sszx301i0x6xysaqzla09nksnd-hello-2.10 + ``` + +# Description + +This command verifies the integrity of the store paths *installables*, +or, if `--all` is given, the entire Nix store. For each path, it +checks that + +* its contents match the NAR hash recorded in the Nix database; and + +* it is *trusted*, that is, it is signed by at least one trusted + signing key, is content-addressed, or is built locally ("ultimately + trusted"). + +# Exit status + +The exit status of this command is the sum of the following values: + +* **1** if any path is corrupted (i.e. its contents don't match the + recorded NAR hash). + +* **2** if any path is untrusted. + +* **4** if any path couldn't be verified for any other reason (such as + an I/O error). + +)"" diff --git a/src/nix/why-depends.cc b/src/nix/why-depends.cc index 57b9a2208..297b638cc 100644 --- a/src/nix/why-depends.cc +++ b/src/nix/why-depends.cc @@ -50,22 +50,11 @@ struct CmdWhyDepends : SourceExprCommand return "show why a package has another package in its closure"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "To show one path through the dependency graph leading from Hello to Glibc:", - "nix why-depends nixpkgs#hello nixpkgs#glibc" - }, - Example{ - "To show all files and paths in the dependency graph leading from Thunderbird to libX11:", - "nix why-depends --all nixpkgs#thunderbird nixpkgs#xorg.libX11" - }, - Example{ - "To show why Glibc depends on itself:", - "nix why-depends nixpkgs#glibc nixpkgs#glibc" - }, - }; + return + #include "why-depends.md" + ; } Category category() override { return catSecondary; } diff --git a/src/nix/why-depends.md b/src/nix/why-depends.md new file mode 100644 index 000000000..dc13619e1 --- /dev/null +++ b/src/nix/why-depends.md @@ -0,0 +1,80 @@ +R""( + +# Examples + +* Show one path through the dependency graph leading from Hello to + Glibc: + + ```console + # nix why-depends nixpkgs#hello nixpkgs#glibc + /nix/store/v5sv61sszx301i0x6xysaqzla09nksnd-hello-2.10 + └───bin/hello: …...................../nix/store/9l06v7fc38c1x3r2iydl15ksgz0ysb82-glibc-2.32/lib/ld-linux-x86-64.… + → /nix/store/9l06v7fc38c1x3r2iydl15ksgz0ysb82-glibc-2.32 + ``` + +* Show all files and paths in the dependency graph leading from + Thunderbird to libX11: + + ```console + # nix why-depends --all nixpkgs#thunderbird nixpkgs#xorg.libX11 + /nix/store/qfc8729nzpdln1h0hvi1ziclsl3m84sr-thunderbird-78.5.1 + ├───lib/thunderbird/libxul.so: …6wrw-libxcb-1.14/lib:/nix/store/adzfjjh8w25vdr0xdx9x16ah4f5rqrw5-libX11-1.7.0/lib:/nix/store/ssf… + │ → /nix/store/adzfjjh8w25vdr0xdx9x16ah4f5rqrw5-libX11-1.7.0 + ├───lib/thunderbird/libxul.so: …pxyc-libXt-1.2.0/lib:/nix/store/1qj29ipxl2fyi2b13l39hdircq17gnk0-libXdamage-1.1.5/lib:/nix/store… + │ → /nix/store/1qj29ipxl2fyi2b13l39hdircq17gnk0-libXdamage-1.1.5 + │ ├───lib/libXdamage.so.1.1.0: …-libXfixes-5.0.3/lib:/nix/store/adzfjjh8w25vdr0xdx9x16ah4f5rqrw5-libX11-1.7.0/lib:/nix/store/9l0… + │ │ → /nix/store/adzfjjh8w25vdr0xdx9x16ah4f5rqrw5-libX11-1.7.0 + … + ``` + +* Show why Glibc depends on itself: + + ```console + # nix why-depends nixpkgs#glibc nixpkgs#glibc + /nix/store/9df65igwjmf2wbw0gbrrgair6piqjgmi-glibc-2.31 + └───lib/ld-2.31.so: …che Do not use /nix/store/9df65igwjmf2wbw0gbrrgair6piqjgmi-glibc-2.31/etc/ld.so.cache. --… + → /nix/store/9df65igwjmf2wbw0gbrrgair6piqjgmi-glibc-2.31 + ``` + +* Show why Geeqie has a build-time dependency on `systemd`: + + ```console + # nix why-depends --derivation nixpkgs#geeqie nixpkgs#systemd + /nix/store/drrpq2fqlrbj98bmazrnww7hm1in3wgj-geeqie-1.4.drv + └───/: …atch.drv",["out"]),("/nix/store/qzh8dyq3lfbk3i1acbp7x9wh3il2imiv-gtk+3-3.24.21.drv",["dev"]),("/… + → /nix/store/qzh8dyq3lfbk3i1acbp7x9wh3il2imiv-gtk+3-3.24.21.drv + └───/: …16.0.drv",["dev"]),("/nix/store/8kp79fyslf3z4m3dpvlh6w46iaadz5c2-cups-2.3.3.drv",["dev"]),("/nix… + → /nix/store/8kp79fyslf3z4m3dpvlh6w46iaadz5c2-cups-2.3.3.drv + └───/: ….3.1.drv",["out"]),("/nix/store/yd3ihapyi5wbz1kjacq9dbkaq5v5hqjg-systemd-246.4.drv",["dev"]),("/… + → /nix/store/yd3ihapyi5wbz1kjacq9dbkaq5v5hqjg-systemd-246.4.drv + ``` + +# Description + +Nix automatically determines potential runtime dependencies between +store paths by scanning for the *hash parts* of store paths. For +instance, if there exists a store path +`/nix/store/9df65igwjmf2wbw0gbrrgair6piqjgmi-glibc-2.31`, and a file +inside another store path contains the string `9df65igw…`, then the +latter store path *refers* to the former, and thus might need it at +runtime. Nix always maintains the existence of the transitive closure +of a store path under the references relationship; it is therefore not +possible to install a store path without having all of its references +present. + +Sometimes Nix packages end up with unexpected runtime dependencies; +for instance, a reference to a compiler might accidentally end up in a +binary, causing the former to be in the latter's closure. This kind of +*closure size bloat* is undesirable. + +`nix why-depends` allows you to diagnose the cause of such issues. It +shows why the store path *package* depends on the store path +*dependency*, by showing a shortest sequence in the references graph +from the former to the latter. Also, for each node along this path, it +shows a file fragment containing a reference to the next store path in +the sequence. + +To show why derivation *package* has a build-time rather than runtime +dependency on derivation *dependency*, use `--derivation`. + +)"" |